I used to be an RC heli addict when I was forced off the bike with a back injury for a year. I'm glad to be back on the bike, those things were putting me in the poor house. The only one I kept is my scale Vario Bell 47-D with its 6 foot rotor diameter

More to the point of the OP is that I can agree the things these 3D helis can do in the hands of a competent RC pilot are absolutely incredible. This is a video of one of the best 3D pilots around
http://www.youtube.com/watch?v=p3nNiUStTE0