I have a dual gasser on mine, meaning it is both a thumb and a twist. I don't use the thumb at all, but got one in case other people ride it. It is all about preference. I grew up racing dirtbikes and stuff, and know how to handle the "loose grip" feeling Roadkill is talking about. I've learned to hold on with my knees and stuff a long time ago, you'd see when I ride I use my legs to hold onto the quad. Anyway, I like it a lot. I've had motionpro on the 450's, and they work alright too. All the ones you will find will be plastic, and will turn a little bit before you actually get to the gas, no matter how tight you try to make it.
2008 700xx; Power Bomb header with power core 4 exhaust, Power Programmer III, pro armor nerfs, prm products control front and rear bumpers and full skid, 10" ITP rears, ITP Baja's fronts, RZR 2's all the way around, Uni filter, 13t sprocket, CCP steering Damper, DS450 shock swap, Dual Gasser Throttle, bar risers and Moose barkBusters. 730XX kit plus other engine mods!