My rating of 4 stars for the iRobot Roomba 650 isn't perfect, but I still bought 2 of them. Partly because these things don't climb stairs. And partly it reflects my skepticism of a Digital Era that promises miracles but falls short of the mark. Even with their warts, however, there's something about these oversized hockeypucks that's oddly endearing.PROS:1.) Cleans about as well as my old Kenmore canister w/beater-brush attachment.2.) Heavy weight (about 9 lbs) allows brushes to fluff carpet pile.3.) Rugged, modular construction.4.) Nifty carrying handle on top, cleverly disguised as decorative trim.5.) Good transition over a variety of floor surfaces.6.) Reliable cliff sensors prevent unit from tumbling down stairwells.7.) Programmable daily scheduling without need for smartphone/Internet/wi-fi infrastructure.8.) Programming of clock & scheduling is easy & intuitive, via big bright red LED's for users with limited vision.9.) The included "virtual wall" unit solved annoying problems; works as advertised.10.) Good for people diagnosed with pelvic/spinal/leg problems that limit their use of a manual vacuum.11.) Ideal for users in single-floor dwellings (apartment, ranch-style home, etc.).12.) Functions any time day or night, even total darkness (I tried this).13.) Lower height profile compared to some later models (like the 690), allowing better penetration beneath furniture & overhang kickspaces around refrigerators & floor cabinets without getting trapped.14.) User-accessible modules are fastened with captive screws; if disassembly is required you need not worry about losing little screws or remembering which screw goes in which hole.15.) The 650 supposedly isn't rated for multi-room use, but I use it routinely for multiple rooms with no docking problems. Docking is 100% reliable.16.) Good value for money at lower end of the price range ($300), a workhorse without bells-&-whistles. Overall reliability about 95%.17.) 1-year warranty on factory-new 650; separate battery warranty is 6 months.18.) Refurbished units have a 90-day warranty on robot & battery.19.) Upon registry of warranty & serial number, Tech Support can tell you when your 650 was made (month & year). Also remove the battery & record the S/N from label on the bottom. Register the S/N of your battery when you register the S/N of the robot. This info is useful to tell how long the 650 sat on the shelf before you bought it, especially if you encounter battery problems.20.) Pretty good Tech Support, above average.CONS:1.) Endemic Issues: All robovacs are too expensive; maintenance-intensive; have battery concerns not found in AC-powered manual units; require a dedicated space in your home; dustbins are too small; user is exposed to particulate aerosols while emptying (allergen hazard); horror stories of robovac encounters with animal waste ("Poopocalypse"); only good on horizontal surfaces; can't be used to clean cars; & require consumable parts not available in most brick-&-mortar outlets that could possibly be discontinued.2.) Factory-new 650's are now hard to find, despite widespread Internet test reports & assurance by iRobot Tech Support the 650 is still in production. Current offerings are mainly "factory refurbished" units. I identified my Amazon-purchased refurb as a 650 variant, the 655 (from Costco). Bad news if there's a major malfunction after the 90-day warranty expires.3.) Product manuals for Roomba 650 & 690 models in my hands are grossly inadequate. iRobot's marketing dept. wouldn't know a decent manual if it bit them in the leg. Written by folks who never used a 650 in real life.4.) The 600 series has no "BIN FULL" indicator (an oversight corrected in later series models).5.) Design Issues: A.) All Roombas built on the 600-series chassis have a possible design flaw in the rubber roller: it traps hair. See my fix below. B.) The 650 caused minor scuffing damage to woodwork & heating vents in my home (paint chipping, etc.). The unit itself also suffered scuff damage to the hard plastic front bumper during my first month of use. Given the random "thump-&-bump" behavior of the product, lack of a bumperguard is unconscionable. See my fix below. C.) The long slender polystyrene door on the dustbin seems flimsy. An open invitation to break that door while emptying the bin. I take caution while emptying the bin, but I can't help feeling eventually I'll have a bad day & then be in for repair hassles.6.) There is no dustbin sensor. The 650 will gladly run around scooping up dirt & spitting it out again if the dustbin isn't in place or the vacuum motor has failed. That's dumb. There should be a sensor to detect the presence/absence of the dustbin & monitor current drawn by the vacuum motor.7.) Your household might not be "robot-compatible": dark-colored floors, multistory dwelling, excessive clutter, infants, no HEPA filter, no suitable place to park it, etc.8.) At least 2 different types of brush-cleaning tools are supplied, either ignored or poorly described in the manuals. The "comb-&-hook" variant (which I don't like) took me awhile to figure out, while the cylindrical type is easy to use.9.) The battery charging control circuit is part of the main PC board inside Roomba. If that circuit fails, the entire unit is shot. Battery problems rank #1 on the complaint list.10.) Add Roomba to your list of Dumb Digital Things that require clock reset for Daylight Savings Time.11.) Manufacturer's website contains an outdated page offering a free gift ($45 free replenishment kit) for 650 purchasers, which expired Oct. 2015. Hello iRobot, is anyone minding the store?12.) Increasing trend for later models to be dependent on Internet connectivity. That scares me.13.) Confusing plethora of models. The 652, 655 (Costco), 665 (Sams Club), & 680 are all variants of the 650. The 652 & 680 use lithium batteries & are available, but cost more.14.) Difficulty obtaining basic product specifications & measurements (as opposed to features & hype) on various models unless you have ready access to the Net. Amazon does a better job informing customers than iRobot or the "expert" blogsites.15.) Warranty registration requires furnishing an email address that serves as your "warranty account". I hate that. Too many companies to whom I entrusted my email address abused it by selling it to other companies & bombarded me with junk mail. I now avoid sharing my email address with all commercial entities, but when required to do so I give a "garbage account" created just for this purpose. If you refuse to give iRobot an email address they assign you a "default" address to satisfy their recordkeeping. It's a poor system, given the vulnerability of email addresses.16.) Concerns about the manufacturer. In 2017 iRobot announced intention to consider distributing floormaps of users' homes (collected by wi-fi models) to 3rd parties. Creepy. I want no part of that.SEMANTICS: I'll be referencing a variety of topics & models, so let's define terms. iRobot Corp. will be shortened to "iR". "Robovac" refers to all robotic vacuum cleaners generally, without specifying any particular manufacturer. I'll use "Roomba" as a generic reference to all of iR's robovac products without regard to any specific model, while "650" is a generic reference to both of my Roomba 650's. "N650" or "Mushmont" refers to the 650 I purchased new, while "R650" or "Rosie" refers to the 650 I purchased as a refurbished unit. I also refer to manuals as "docs".ROBOVAC vs. MANUAL VAC: Robovacs are intended for maintenance cleaning only. On the basis of versatility & cost-benefit alone, the crummiest manual canister vacuum beats the snot out of the best robot. So why buy a robovac?FITNESS OF PURPOSE: I have 2 problems. First, I have several lumbar vertabrae fused to my pelvis. Forget about touching toes, I barely reach kneecaps. Every year my old Kenmore gets harder to use. Second, I have several Norway spruce trees on my property. Giant Christmas trees shedding tons of sticky pine needles. Needles everywhere: car engine, bed, furniture, & permanently embedded in the carpets. Nobody walks barefoot or stockingfooted around here unless they enjoy pain. The amount of manual vacuuming required to remove the needles would consume my life, if it didn't kill me first. So the prospect of an automated machine to tackle this task is appealing.THE RIGHT ENVIRONMENT: Robovacs aren't for everyone, as noted above. Fortunately my dwelling is "robot compatible". My home is a modest 1500-sq.ft. split-level with 4 floors: Ground Level & Floors 1, 2, & 3. The layout is basically 2 stories chopped-up into 4 half-floors by a central rectangular stairwell-&-closet core. Floors 1 & 2 get the most traffic, also the most dirt & pine needles. The 1st floor is shaped in a sideways U with wide-open access around the stairwell core: livingroom on the front side of the U, dining area at the bend of the U, & kitchen on the back side of the U. At the tail end of the kitchen is a stairwell leading down to a family room on the Ground Level. A stairwell in the livingroom leads to the 2nd floor, where there are 2 bedrooms, bath, hallway, & stairwell to the 3rd floor. I use one bedroom as an office. Within this warren of rooms & stairwells I found nooks where a robovac can live without getting trampled.HOME SWEET HOME: Photo 1 shows my two 650's (N650 at left, R650 on right.) The semicircular band around top half of the unit is a recessed carrying handle. N650, with his black livery resembling a butler in tuxedo, is Mushmont (a suitably stuffy name for the hired help). Photo 2 shows Mushmont at home, tucked under a record cabinet in my livingroom (yeah, I still listen to vinyl). Despite cramped quarters, "Mushie" has never failed to locate his dock at the end of a run. (This is where knowledge of robovac dimensions is critical, since vertical clearance for Mushmont is less than 1 inch & his width imposes limitations on placement of the dock. iR's manuals & packaging are woefully deficient providing such detail.) R650, in her pale grey apron reminiscent of a scullery maid, is Rosie (the outdated robot maid in the "Jetsons" TV series). Photo 3 shows Rosie in her nook upstairs. The stairwell beside her isn't a problem, since it leads to the 3rd floor which is seldom used. Mushmont cleans the 1st floor, while Rosie tends after the 2nd floor. Much better than carrying a single robot up-&-down the steps to clean both stories, which is why I bought a 2nd unit. I don't have any pets, so this review is bereft of entertaining animal-robot encounters.BOTRUNNING: After setup, charging, programming, & basic checkout of components to ensure nothing was damaged, I commenced field trials to determine functionality & establish the level of trustworthiness. At exactly 3PM, both 650's awaken with a short melody, back away from their docks, execute an about-face, then go charging out to wage war against dirt. There are umpteen online reviews describing the crazy antics of these machines, so I'll skip that part. It's entertaining at first, but the novelty wears off. On his first run I was pleased to see Mushmont spend a long time in the vicinity of my front door, running in circles with the blue DIRT DETECT light blinking. That area of my livingroom is the most heavily soiled & contaminated with pine needles, so the excess time Mushie spent there was warranted. Upstairs, it was immensely satisfying to watch Rosie plow furrows through entire tribes of dustbunnies that were breeding under my bed for generations. This is one of the few areas where the robot outperformed my clumsy attempts with the old Kenmore, since long reaches under a bed with a horizontal tube are unwieldy. A typical run lasts roughly an hour. About 45 minutes into the run, the green DOCK button begins pulsing slowly, about once/second. That means Roomba has decided to go home. With the DOCK light blinking, a 650 might continue cleaning for quite some time before it finally locates the dock & quits. (This behavior isn't described in the manuals.)THE DOCKING DANCE: Even after living with these critters for several months, I still find the docking process fascinating. As Roomba approaches the vicinity of the dock, you can tell it has "locked on" to the dock signal because the unit will turn toward the dock & the blink rate of the DOCK light increases dramatically, to about 5 or 10 times/second. If the approach angle is too acute for a proper dock, 650 will back off, move to a better angle, then turn & approach the dock at an angle closer to 90 degrees. I found that uncanny, since it mimicks human action when negotiating a narrow parking space. When it gets about a foot from the dock, it suddenly slows down & commences what I call the "docking dance". The 650 makes minor course corrections & "wiggles" gently as it gets ever closer, until it finally pulls onto the dock & congratulates itself by playing a little melody. (Again, none of this behavior is described in the manuals.) A green LED atop the dock flashes briefly to welcome the 650 back home, & 650 responds with a slow-pulsing amber CLEAN button for about 30 seconds. Then all the lights go out to save energy, & Roomba recharges for the next run. While on the dock, you can get an idea of the state of the battery by pushing the CLEAN button once. If it blinks amber, 650 is still charging. If green, recharge is complete & the dock is just "topping off" the battery.EFFICIENCY: The color of my carpet is best described as "camouflage upchuck". It does a great job of hiding dirt--a mixed blessing. After the 650's first run, there were areas on both floors that were missed entirely, or not completely cleaned. That's normal. These older models operate randomly & achieve maximum efficiency by going out day after day until by sheer statistical probability they eventually cover the entire area. Their true measure of performance is brutally revealed when you empty the dustbin. (I wait until the unit has docked, then remove the bin without disturbing the machine. Roomba doesn't mind this, since there's no sensor to detect a missing dustbin. If you disturb a 650 while it's asleep, it raises a fuss & blurts out spurious error messages until you re-dock it.) Even if you've recently vacuumed manually, a 650 will surprise you with the crud it finds. Maybe this stuff was there all along, but with a manual canister vac that collects your effluvium in a disposable bag you just never see it.DEVIL IN THE DIRT: I was appalled not only by the quantity of dirt in the dustbins, but also the nature of it. Mushie collected hair, pine needles, fine black dirt, & particulate matter that included several screws, a paperclip, some wire, bits of old food, & assorted unidentifiable detritus. Upstairs, Rosie collected a huge amount of soft lint, 11 cents in change (a penny & a dime), & several pills I dropped on the bathroom floor. The lint was so densely packed, it fell out like the pelt of a dead animal. After several weeks of daily runs, Mushmont's gleanings now consist mostly of mangled pine needles, while to my dismay Rosie is still scalping legions of dustbunnies. (Those strange noises under your bed at night are the conjugal activities of dustbunnies. You know how rabbits are.) My municipality requires recycling, so I keep extra grocery bags next to the kitchen trashcan for sorting paper, metal, etc. I added another bag for collecting Roomba dust, in case any lost diamonds or $100 bills show up in a 650 dustbin.NOISE: Some online reviews complain how noisy Roomba is. Well, noisy compared to WHAT? I hold these complaints to be unfair. Both of my 650's combined are more quiet than my 40-year old Kenmore canister vac, which in turn is more quiet than my mother's vintage-1962 Kirby upright that thundered like a 747 on landing approach. Our perception of sound is highly subjective. Even my two 650's don't have the same acoustic signature. Mushmont sounds like a tired coffeegrinder, while Rosie is more of a rattletrap foodprocessor. These sound qualities are inconsistent, since they change according to the type of floor surface. A typical Roomba has 5 electric motors. Four of those motors have a drivetrain of gears, so there's gear noise in addition to motor noise. This is a highly mechanical device, & it's unrealistic for anyone to expect something with 5 motors to run silently. I suspect noise complaints are probably related more to the unusual nature of the noise than to its loudness. Most manual vacs have a "whoosh" that people are used to. But Roomba's acoustic signature comprises only about 20% of that "whoosh" sound, while the other 80% is an unsettling combination of clashing gears & straining servo motors. This ain't your mom's vacuum cleaner. It sounds more like, umm... a robot.PROBLEMS: As mentioned in Item 5 under "Cons" above, I encountered a problem with the 650's rubber roller. The area between the rubber blades & dustguard at the end of the drive side of the roller, collected hair so tightly wound around the shaft it could only be removed by repeated cutting with scissors. Basically your classic Gordian Knot. This happened 3 times during the first week. Photos 4 & 5 show the problem. What was needed was to fill the space between the rubber blades & dustguard (orange arrow in Photo 4). My solution is shown in Photo 6. I fished up 2 small plastic washers plus a larger one. I cut a slit in each washer & slid them over the roller shaft. The 2 small washers proved insufficient to fill the space completely, so I piled on more filling by wrapping the space with teflon tape. Problem solved. It might have been easier to use hotmelt glue to fill the space, but around here we don't argue with success.The 2nd problem, also mentioned in Item 5 above, is visible in Photo 7. This pic shows damage caused upstairs by Rosie, but Mushmont clobbered a heating vent in my kitchen with similar paint-scrape damage. My cure is shown in Photo 8. It's a thin clear vinyl apron attached to the front bumper (green arrows), secured at each end by black vinyl tape (yellow arrow). The product is patio door self-sticking weatherseal tape made by Frost King, available at hardware outlets for about $7. The roll of weatherseal was long enough to fix both 650's with plenty left over, & the width is a perfect fit for the 650 bumper. It's thin enough to not interfere with docking. I resent making this fix, as I strongly feel iR's engineers should have incorporated a soft bumperguard into the Roomba product line from Day One. It's just common sense. Either somebody in Engineering wasn't earning their pay, or someone in Accounting shaved nickels off production costs. I got $600 invested in Colin Angle's technology, & I'm plastering it with tape to protect my woodwork. How absurd is that?OOPSIES: While neither 650 has ever fallen down a flight of stairs, about 10% of the time they got stuck at the top of a staircase & cried for help. Mushmont got stuck 3 times at the top of the kitchen stairwell leading to the family room. Rosie got stuck once, at the top of the stairs leading to the livingroom. A Virtual Wall placed at the stairwell in the kitchen reduced overall stairwell mishaps to near zero. Establishing trust in a robovac is imperative if they are to function without a babysitter.Another oopsie involved doors. One day I was in the bathroom attending to a natural function. The door was closed but I had failed to engage the latch. Rosie was outside vacuuming the hallway. Suddenly the door flew open & Rosie came barging in without so much as a "Pardon me!" Being in a compromised position, I just let her do her chores. Edging along the wall on the way out, she managed accomplish what I had failed to do: she slammed the door shut with enough force to latch it. Now both of us were shut up in the bathroom, blocking her return route to the dock. She nudged around the perimeter of the bathroom, vainly seeking to escape. I hurriedly concluded my business & let her out. These days I'm more careful about doors.In any environment where you have entities capable of independent locomotion (people, pets, robots), it's inevitable that 2 of those entities will collide. I've seen a few online reports of painful human-robovac encounters, which puzzle me. Now that I'm acclimated to the noises a 650 makes, I no longer pay them much mind. That allows Mushie to sneak up on me while standing stockingfooted at the kitchen sink, where he has bumped me several times. An odd sensation, but never painful. If you ever fed a hungry cat that walked all over your feet, rubbing your ankles & bumping your legs, that's what it's like.MANUALS: If I list all the problems with the 650 docs I'll end up rewriting iR's manuals for them. Docs for the 650 are the weakest link in the Roomba product line. I have 3 separate manuals for the 650: 2 that came with the units (dated 2015 & 2016) & one I downloaded from the Net (dated 2012). All of them are poor in various ways. None have a product specifications page listing dimensions, product wt., shipping wt., battery data, significant features, & just basic info for anyone unfamiliar with such a complex product. Best of the lot is the one furnished with N650, a 38-page booklet printed in English & French, dated 2015. This manual does a decent job informing a novice how to use & maintain a 650. But there are errors in the diagrams, a glaring error in the instructions (p. 31), & numerous omissions. (I owned N650 for a month before I discovered the carrying handle wasn't just decorative trim. I'm not an idiot, but the faulty manual made it seem so.) Docs furnished with R650 were even worse. To its credit, I did at least find out about the carrying handle from the R650 docs. But in all other respects it was less valuable than toilet paper. Maybe iR doesn't care about customers. When you control 88% of the market, perhaps you can take customers for granted. Or maybe iR just has their noses stuck so far up into their technology they've forgotten how to communicate with legions of potential buyers who don't know diddly about their products but are seriously interested if the price is right. I've seen negative online reviews where disgruntled buyers returned a Roomba more out of ignorance than defects. So sad! Perhaps if Angle & Co. spent less time with self-promotional hype & "enhancing shareholder value", & more time giving current & prospective buyers better info & docs, their already-successful business would continue growing without Wall Street busybodies looking over their shoulders.BATTERIES: If docs are the weakest link in this product, batteries run a close second. There's an Iron Rule about rechargeable batteries: The worst thing you can do to one is not use it. A busy 650 is a happy 650, so I advise programming it to run every day, or every 2 days at minimum. The 650 docs do caution users not to allow Roomba to stay discharged for any length of time, & to keep it docked when not in use. Roomba DOES draw continuous current from its battery even when it isn't running (not mentioned in the docs, of course). The 650 ships from the factory with a 3000mAh NiMH battery installed, albeit disconnected. Pulling the yellow tab from the bottom of the unit when you unpack it connects the battery & activates the unit. Roomba then begins drawing down whatever charge remains in the battery from the factory. That's why the docs instruct you to charge Roomba overnight before use, & it's also why you should register both your product & battery serial number with Tech Support ASAP, to find out just how fresh (or ancient) your 650 & battery are. Very roughly, any battery less than a year old should be OK. Anything older than that, you're rolling dice. There are 2 different types of 650 batteries: the standard yellow APS (Advanced Power Systems) battery, & a special blue XLIFE (Extended Life) battery claimed to last longer than the APS type. My experience is that it's better to have a FRESH battery of any kind than a fancy XLIFE battery made in ancient Rome. My N650, purchased early Jan. 2018, arrived with the standard APS battery. From iR serial numbers, N650 was made Mar. 2017, & its battery was made Feb. 2017. After 9 months on the shelf, there was still enough juice in N650 for it to fire up with a green button & make its own way to the charging dock by pressing the DOCK button. Not so with R650 (the refurb unit). R650 arrived in Feb. 2018 with a dead battery. Well, not entirely dead. When placed in front of the dock & the DOCK button pressed, the CLEAN button glowed red. Not good. I nursed R650 onto its dock by hand (not fun). Battery performance slowly improved with use, but after several weeks I was doing good to get 20 minutes out of Rosie. Again from iR serial number data, R650 was made Nov. 2016, but its fancy XLIFE battery was made June 2015... almost 3 years old! After several calls to Tech Support & experiments with deep-cycling the battery, iR finally sent me a brand-new XLIFE battery. By communicating my concerns early in the warranty period Tech Support treated me fairly.MAINTENANCE & CONSUMABLES: I've not yet had to purchase any spare parts, but I'm looking. I'll need replacement filters & spinning sidebrushes, & later on some replacement rollers. You can delay buying filters by re-using them. Run them under warm water, clean with a soft brush & any detergent (old toothbrushes are best), rinse & pat dry with a clean paper towel. Only takes a minute. Eventually the cheap polyurethane foam seal wears out, then it's New Filter Time. While you're at it, run the rubber roller under the faucet & use the same paper towel to dry the rubber blades, another 1-minute process. Save that moist towel to wipe the clear lenses of the cliff detectors, then the interior of the dustbin after emptying. It seems to me the spinning sidebrush, with a little re-design, could have its lifetime doubled. The problem with the spinner is that eventually the brushes get bent from turning in the same direction. If someone could make a spinner that's REVERSIBLE, when the brushes get bent you could turn it over & continue using it until a brush arm breaks off. Hello entrepreneurs, vendors, iRobot- anybody? Hint, hint, hint... .BRICKS IN THE BEDROOM: I have no intention of wrapping my life around a household appliance. On the other hand, if minor adjustments are needed that can be implemented with minimum effort, one must be reasonable. I relocated my bathroom scale to allow Rosie access to the floorspace formerly occupied by the scale. Likewise, I now lay my terrycloth bathmat over the side of the tub instead of on the floor. The first time Rosie encountered the thin bathmat, she left it in a crumpled heap after shoving it all around the room.The bedroom posed a different problem. My home was built in 1956, when there weren't as many electrical gadgets as we have today. Homes built back then suffer a miserly shortage of AC outlets. The bedroom has only one outlet that's overloaded with gadgets. There's a regular pasta-plate of wiring along one wall that coagulates into a snake's nest between the bed & nightstand. Some of the wires are routed over a heating vent that has worked loose over the years. Rosie never got tangled in the wires, but she clobbered the vent & dragged the nest of wires halfway under the bed. My solution was crude but effective. Three bricks, placed at strategic locations along the wall to block Rosie's access to the wires & vent. Problem solved. I don't mind the bricks, since they're out of the way & not visible to a casual observer.My office is another matter. It's Clutter City in here, with 11 major furniture items & miles of electrical cords to power PC's & assorted office junk. Maybe one day I'll get the place cleaned up enough to be safe for Rosie, but for now her access is limited to the first 5 feet of the entranceway. A 2nd strategically-placed Virtual Wall prevents her from invading the inner sanctum of my office.THE FUTURE: The very fact I haven't returned these machines speaks volumes. I purchased them as an experiment, & thus far it seems things are working out for me. But robovacs don't clean steps, cars, walls, or furniture, so I'm not about to trash the old Kenmore just yet. I worry about the direction iR seems to be going. Now that it's a multibillion-dollar outfit, iR is behaving more like a creature of Wall Street than the startup tech-shop it once was. Their marketing is a disaster, & the latest 800/900 series robots seem to be numbered after their prices. I averaged $300 apiece for my 650's, which for a retiree on a fixed income is a fortune. Thus far I've received value for my money compared to my needs, so I can't complain. But anyone who spends $900 on a glitzy-frills vacuum cleaner needs a doctor. If iR aims to market the latest Roombas to the lunatic fringe, what does that say about the executive leadership? The business model seems to be shifting away from a reasonably priced commodity appliance toward data collection about your private home, which is a whole different ballpark. This despite clear sales patterns fairly screaming that ordinary folks like me want a simple, affordable, programmable, dependable, non-wifi 650-type machine. It's no accident that after lengthy research & a brief <disastrous> bad start with a 690, I landed on the 650 as my best all-around choice. The 650 has been a runaway best-seller. On Amazon alone, there are more product reviews (6600 & counting, including refurbs) than all other Roomba products combined, with a very respectable overall score around 4.3/5.0. I'm glad I got my sensible 650's before iRobot Corp. goes off the rails.