I'll be renting two scooters in December. I've rented before and the one thing I've learned is that all the rental companies are great until you have a scooter that doesn't work. Good advice by a previous poster is to have the phone number of your rental company in the park.
I will go with a featured vendor; because, they have resort drop off privileges. I just couldn't tolerate waiting for a scooter vendor to come.
I haven't quite decided who I will choose yet, but I'll keep watching here for experiences of others in this regard.