Let me put my two cents in on the three v. four wheeled issue! I think the three wheeled variety turns MUCH BETTER than the four wheeled! My little three wheeled Golden Buzzaround Lite can turn on a dime, which is critical for things like the lines in Disney, getting in and out of handicap bathroom stalls, avoiding people who don't look below eye level, etc. It turns on a dime, which is excellent!
HOWEVER... part of my maneuverability is in its light weight, and that light weight comes with a cost. Battery power!
When I got the scooter, a major part of my decision was that I needed to, if necessary, be able to put it together myself. This model was the only one that fit the criteria, as the heaviest part is only about 20 pounds, and I can easily grip it with my arthritic hands. The battery pack, though, is about 12 pounds, and locks in easily. It does have to be charged regularly, and it only lasts around 3-4 hours, I think. I have really never put it to the test completely, as I charge it whenever I stop for more than half an hour or so. Every time we stop for a meal, I plug in. Stop for a show, I plug in. Parade, I plug in. See a pattern emerging?
Its the smallest
ECV out there, and absolutely the easiest to maneuver and get through crowds (especially when the crowds consists of skateboarding college students - y'all didn't think Disney was my biggest challenge did you?

) I'm really kind of like a moving chair, LOL! Especially since my basket fell off... but that's another story.
I wouldn't recommend this for anyone that does commando park hopping, or anybody tall or Pooh sized. I'm only 5'1", and if I were much taller the tiller might hit my knees, if that gives an indication of how small mine is. The weight will drag the speed and battery life down, as will any of the ECV's, I guess. But there is plenty of room in the front to stretch my leg out, even when wearing my knee brace, FWIW.
I'm looking at new models, though, since this one is about 5 years old. I've been through 2 batteries in that time, and now the post that holds the seat in place is about to jolt me to death. I'm still going to stick with Golden, I think, but go up to a bigger model, since I'm not going to be teaching full time anymore.