All right. I figure it's about time to write up a review of these headphones, seeing as I've spent some decent time with them and the Christmas sales should be happening and some of you may be wondering if you should spring for these - OR - wait it out until the next model Mk IV eventually shows up. The most frequent question I get is "How long do these last with Noise Cancellation on?" With the ANC (active noise cancellation) function ON - I've seen about 22-24 hours or so of Bluetooth-connected operation with these. The noise cancellation operation / ambient sound mode of these headphones are run entirely by the internal charged battery. Someone asked me a while back if with the headphones connected to your phone via the headphone cable, if they would still have noise cancellation / ambient sound mode even if the battery was dead and the answer is no, no they will not. You can still listen to music through the 3.5 mm physical cable with a depleted battery, but noise cancellation will not be available. Actually, you also can't use Bluetooth / noise cancellation when even in the process of charging these headphones… (see "gripes" towards end of review).. so I guess it's good Sony decided to bestow a quick-charge 5-hour use time after a 10-minute charge function into these (using a wall receptacle USB adapter of course). Basically how it works is if you have an energized battery in the headphones you can use the noise cancellation and the Bluetooth connection - which also serves to activate the right ear cup touch-pad to perform functions on the headset. If you have an energized battery and decide to use the direct 3.5mm headphone cable to connect to your phone or computer instead, you can still use the noise cancellation, but the touch-pad will not be available to utilize as the cord now takes over for Bluetooth to serve music (and as it depends upon the Bluetooth connection to "talk" to the paired device for functions, the touch-pad is disabled). If you have a depleted battery you cannot use noise cancellation or the touch-pad but you can still get sound out of them like a regular pair of headphones by using the 3.5mm cable plugged into your phone or computer. The connectivity through Bluetooth seems really robust. I have had only one minor issue since owning these where the sound of what I was listening to hiccupped out for a fraction of a second a couple times, but I think it had more to do with my phone not behaving at that moment and not the headphones themselves causing the problem. Walking around inside or outside or for traveling, the connection has remained stable since. How "Good" the active noise cancellation works in any pair of headphones is somewhat subjective... but I can say these work really well, bearing a few things in mind and that we've not quite reached the technological level yet of producing truly silent headphones the quiets absolutely everything. Not for $350 dollars anyway. The headphone Manual itself states that "Noise Cancellation" works primarily in the low frequency band and that although noise is reduced, it is not completely cancelled. I can best equate the effect with just the active noise cancellation mode on and with nothing playing through them, to having a good set of hearing protection earplugs in your ears. Everything sounds reduced, especially things like dronning, humming, knocking and footsteps...there is a general quieter sound you experience, but you're not left completely oblivious to some noise coming through a little. These headphones will not surround you in a magical protective vacuum bubble when you have them on. However: The real magic happens when you start playing music through these headphones or listening to a movie or such. With the active noise cancellation diminishing the outside sound pretty well all on its own, the sonic enjoyment of what is playing through the headphones is not restricted at all... you get full volume, clarity and bass and that simply causes the outside world to melt away, leaving you with a little comfort-cocoon that really does impress. I have had very good success with these headphones canceling out unwanted noises and / or being able to enjoy what I want to listen to across a range of scenarios: Noisy Neighbors next door doing noisy things, kids pounding around upstairs in the house, traveling in the car (as a passenger of course - not driving!), a couple bus commutes, and so forth. As for the sound quality, I will say that they are very good. These are not high-end audiophile reference headphones costing thousands of dollars, but there is definitely high-quality audio out of these with a nice sound stage and separation with additional tweeking you can do through Sony's Headphone Connect application to adjust equalization and bass. These are not the loudest headphones I've ever used... I've had models that are almost obnoxious in their power delivery, to the point of being painful to listen to with the volume all the way up. I am the type of listener who likes a bit of punchiness in their music, but also appreciates nuances over ham-fisted bass slamming into my ear canals at the expense of everything else...and I will say that with the noise cancellation feature turned on, I'm actually enjoying music at a lower volume level than I'd need with other headphones. The WH-1000XM3's ability to effectively mute the outside distractions allows me to concentrate on what I'm listening to, and I don't need the volume cranked up to enjoy a range of music. I did have to tweek a few things with the app to suit my preferences, but I am left very happy with what these can deliver. Of note, you can set two "Custom" EQ settings in the app, so one you might use for punchier bass and the other for higher treble or vocal listening. The weight of these is impressively light. I might have been initially expecting them to have a weightier feel... maybe because I was thinking that with the added components necessary for noise cancellation, those would increase the headphone weight by several ounces. I'm happy to report that these headphones are able to be worn comfortably for extended duration with no feeling of pinched ears or sore spots. The ear cups on the WH-1000XM3's are of a more oval design than circular as found on my older Sony MDR-XB950BT headphones, and this makes them very comfortable to wear even laying back on a pillow or car seat. The thick padded circular ear cups on other headphones tends to press up against the back of a pillow or seat, and causes some pressure and discomfort against the back of my ears if worn too long when reclined. No such issues with these. I have seen a few complaints online about people reporting that their ears get warm after wearing these for a while. Having spent some time with these, I personally think it's the effect of just wearing a pair of closed-back headphones with snug-fitting padded ear cups causing this. Every pair of closed-back headphones I've worn with padding that encapsulate your ears will get to feeling a little warm after extended sessions with them on. For me personally, I have not had discomfort with these on even after a few hours of listening to music and watching a movie with the noise cancellation activated. The Phone Call microphone is something that many people seem to have initially hated on these headphones - many comments about how "it's garbage" and so on, reside on the internet. I am not sure where the hate is coming from, as I've had no issues making or taking phone calls with these, and nobody has complained about the call / microphone quality. Maybe Sony updated something in later production runs, but for whatever reason, the microphone seems fine on my pair. Certainly no worse than other headphones I've used. I will note that I did update the firmware to version 4.2.2 when I first fired-up the Sony App and when I used the headphones for the first time, so possibly that update may have corrected previous microphone problems. I have tested charging the WH-1000XM3's using an Anker PowerCore II 20000 battery bank and with a longer Anker USB-C to USB-A type cable than what Sony provides (see quibbles below), and they work together fine. The Anker battery bank will certainly output a 1.5 A current or more easily, which is what these headphones require for standard charging times. In conclusion, I am very happy with the Sony WH-1000XM3 headphones. Some people may consider these to be really expensive at $350 dollars US, but I don't think thats necessarily true. They're about $100 dollars more than other good quality headphones with similar performance sans active noise cancellation. Is the extra $100 bucks for having ANC worth it? To me, Yes. Definitely. The noise cancellation ability of these has allowed me to enjoy quiet time and listening pleasure that otherwise I wouldn't be able to have with regular headphones. You'll have to decide for yourself, but in a world with an ever increasingly loud and invasive noises you have to contend with daily, I've really really gotten to love using these, despite a few issues I don't really like. **************************************************** Some minor quibbles: A literally 6-inch long USB-C to USB-A power cable, Sony? I just shelled out $350 bucks for a set of your headphones and you stuck me with a barely-useable power cable, never mind no included USB power adapter? You couldn't get the bean counters to authorize even a foot of cable? Jeeze. If you buy these headphones you are going to for sure want a longer USB-C to USB-A cable to charge these with. Anker has some nice ones you can get right here on Amazon. The right-hand ear cup touch-pad is novel, and it has worked for me fine. My only little grumble about it, is the function to pause the music or accept a phone call requires you to do a quick double-tap with your finger on the center of the ear cup touch-pad. Problem is, my ear is in there and the sound of my finger quickly tapping it makes a loud "Thump-Thump!" sound I find annoying. I would have MUCH preferred a physical button instead. I picked the "silver / grey" model color of these headphones, simply because they looked a bit different than the boring ol' black every other headphone comes in. I have noticed that depending on the color temperature of the surrounding light, they can appear to look anywhere from a silver / grey coloration to more of a champagne / very light tan in color. It's not off-putting, and I do like the color of the headphones... but some of you may not appreciate the reactive effect these have in either cool or warm colored light. Figured I'd mention it. My big gripe: You cannot CHARGE these headphones and at the same time, listen with them using Bluetooth or with the ANC on. That seems backwards as Hell to me, considering I probably own at least 10 other electronic devices that CAN be used WHILE they are charging. My Smart Phone, yup. DSLR camera, sure. Voice Recorder, indeed. Graphing Calculator, Uh-huh. Sony MiniDisc Player from literally 15 YEARS ago? YES. So why is it that with these modern $350 headphones, you can't plug them into a usb wall adapter, laptop, or battery bank with a USB-C cable and keep enjoying ANC and Bluetooth connection and listening enjoyment while charging? The moment you plug the USB-C charging cable into these, you lose all Bluetooth and ANC, and the sound shuts off until you stick the physical corded 3.5mm cable into the audio source…which at this point means you're now using a pair of regular headphones because again: No Bluetooth, no Active Noise Cancellation going on. Very very strange, and although with 20+ hours of listening on tap with a full charge, I still question if this isn't something that really should be improved upon with version Mark IV. Wishes for FUTURE: Improved ANC with better elimination of higher pitched / sharp noises, maybe an available headphone stand that can provide the headphones with some type of inductive charging might be nice. Oh, and let us be able to charge AND listen to these with Bluetooth / ANC active at the same time please, Sony.