In a nutshell:
Pro's
+Powerful, 12v 2-speed - moves (2) 50 lb children (100 lb total) on even ground through grass and over tree branches (w/ governing screw removed)
+Two-seater, carries two children seated in front comfortably given the total weight is within reason (<120 lb?)
+Included dump bed w/ tailgate, carries rocks, toys, and sometimes another child (warning: children may fall out!)
+Braking, the vehicle locks/brakes the tires when the accelerator is fully released
+Packaging, smaller pieces shrink wrapped and kept together
+Customer Support, responsive
+Aesthetics, looks tough for a child's toy
Con's
-Lack of horn, seriously?
-Seat belts, not an absolute necessity but older models had them
-Flimsy in places, dump bed tail-gate is very weak and the vehicle floor could be stronger
-Instructions, I hope you like pictures because that's all you get.
We purchased our Gator at a local brick and mortar for a similar price to Amazon (very popular but the chain shall be the Unnamed). Overall, the product is great. It is a wonderful toy given it has faults - just be cognizant that it is not perfect. I purchased the unit knowing the complaints with the stock battery units. I didn't take a chance and was preemptive in buying another battery. The experience has been positive thus far. Dropping a few extra dollars on an aftermarket battery is a good idea.
I went to a local battery specialty store and bought a 12v deep-cycle aftermarket battery (~$40) to replace the OEM. Aftermarkets can be bought cheaper but I settled. You can strip the external OEM battery housing w/ the electrical connector harness and install it directly onto an aftermarket battery of similar size and make (sealed, safe). It was a breeze to install (stock harness uses a spade connector that matches the aftermarket battery) and fits perfectly. My kid was riding it as soon as I put it together as the aftermarket battery was already charged and playtime was over before the battery died (2-3 hours of playtime). The aftermarket charges using the stock charger.
The included toy documentation had numerous warning inserts about never letting the battery run dead (which causes permanent damage) and ensuring a 100% charge before first use. That may indicate the battery complaints posted on Amazon involve improper battery usage/recharing. However, the fact that these warnings were printed on inserts (rather than in the instructions) indicates to me that this was something the manufacturer probably added after initial sales. Repeated customer complaints? Make your own judgments.
As to battery access issues listed on other reviews this is not a problem. Leave the screw that holds the battery compartment out as there are two strong clips that hold the compartment shut - the screw is unnecessary. Slide out a steel retention bar and just be sure to route the wiring on top of the battery unit before pushing it into the compartment. Slide the bar back in, slap the cover shut. Ride on.
The instructions are a particular annoyance - they contain only pictures and sometimes you don't know what you're looking at in a diagram for a few moments. There are no verbal instructions. Be aware there are two sets of instructions - the large main booklet but also a smaller booklet inside the lining of the screw package (tells you which screws go where). I didn't see the screw booklet until after it was assembled. The stock pictures in the instructions/promo materials are sometimes necessary to assemble. This is not a showstopper but it can be aggravating with a 3 year old harassing you to hurry up - "Is it done yet?".
The vehicle moves my 43 lb 3 year old and his similarly-weighted cohort without problem. I removed a speed/power governing screw listed in the instructions/on the vehicle - 1st gear is just too weak. The vehicle zips over *even* terrain, bushy grass, and large fallen branches with ease here in the suburbs - YMMV. I can't comment directly on performance with inclines but I'd expect it to operate fine w/ 50-75 lbs uphill on a good battery charge.
The dump bed is nice although the tailgate is very weak. Riding in the back is possible but one child did fall out as the plastic surface is very smooth and the tailgate flips open easily. Despite the warnings I'll be putting some friction tape in the bed and probably remove the tailgate - stopping other children from clamoring into the back is an effort in futility.
I ran into an issue with the bolts molded into the seating pulling out. This was after screwing some retention knobs to secure the seating. This didn't make the toy unusable but this was not a cheap ride-on - not something you'd want to see. Peg-perego will be replacing the seat without issue. I suggest being very easy on tightening the retention knobs when installing the seating (on the easy end of "hand tight"). Be sure to check if the knob spins and feels "stripped" - it's not the knob that is stripped the bolt is actually loose of the seat molding and needs replaced.
The vehicle body itself is flimsy in some areas. The flooring could be a millimeter or so thicker due to pouncing children and the windshield is held on by only two small screws. Replacement parts can be purchased cheap, though.
The Gator we purchased does not have seat belts although it is evident that other versions did at some point. I do not believe it is necessary for helmets given the vehicle speed. However, I will be purchasing some nylon straps for seat belts to prevent passengers from getting in/out of the vehicle while moving - that poses a greater danger.
My kid and his friends love the Gator and I will probably be adding LED headlights, horn, and tail lights to the unit.
Update 06/07/11: The Gator still runs like a charm with the batteries functioning as they did last year. I kept the batteries out of the winter weather and recharged them once/month. The other Power Wheels brand ride-ons that other children have seem to move at about half the speed of the Gator...I'm not sure if the PW's are 6v or 12v or if the batteries were not well cared for.
The retention knobs underneath the Gator's seat came undone from vibration (then were lost) but the seat sits in place fine. I plan to fix the seat with a large washer and nut. The Gator rides fine without the retention knobs, though.
The tires are wearing but in no danger of needing replacement. This is despite about 4 hours of use per week during warm weather.