Did look at though never rode one of those mp3, three wheeled scooters. Read the 500cc had more power though seems a batch of them had issues with pistion heads or some such thing.
Saw that Yamaha might be coming out with a three wheeled scooter, now that I would trust more then the mp3 model. Rode a Spyder in Daytona as a demo ride, a bit scary for my taste yet the concept, as applied in the mp3 and Yamaha hold interest to me. Safety related primarly.
http://www.autoevolution.com/news/yamaha-confirms-lmw-their-3-wheeled-scooter-video-62742.html