So far (two weeks out) it meets all my expectations. At 72 y.o., I was not sure I could still do this. But I can. Having the seat was necessary to start using it confidently. The center of gravity is lower when you are sitting and stopping and starting are much more stable when your butt is connected to the scooter. That said, with some time to get used to the jerky throttle, I now can ride it standing though I am not, and probably will never be comfortable standing at 34 mph. I've had two serious bicycle crashes that put me in the hospital with months of recovery and I guess I'm a little gun shy (i.e.smarter) now about speeds and road hazards, especially since I probably don't heal as well as I did ten years ago.
Concerning the seat specifically: It is heavy and my bicycling sensitivity to weight thinks this is bad, but compared to my 220lbs., it is insignificant. The seatpost (office chair / pneumatic riser) compresses a bit when sitting and there is some minor looseness/rocking between the parts that is necessary for the proper operation. I thought about making a solid tube seatpost that would be lighter and have no play between parts but I would lose the suspension seatpost comfort, so that's on the back burner. The seat is VERY soft compared to a GOOD road bicycle seat and if you ride for more than ten minutes, you will need to stand for a few seconds and get some blood into your soft tissues (muscle, fat, nerves, etc). It will also compress your pudendal nerve which you won't feel until you get off and you realize your "member" is numb and comes back awake tingling. I may change the seat for one that is more firm, has more ischial tuberosity(sit bones) support, and better pudendal nerve clearance. In the meantime I will just keep standing for a few seconds every ten minutes or so. BTW, absolutely watch the video (in Resources tab of this website) on seat installation BEFORE you try to install it. I nearly had the thing completely disassembled before I looked at the "directions". What can I say; it's a guy thing.
Conclusion: Very Satisfied.