If thumb throtle's were so great all motocross bikes would have them as well, I feel that you get better throtle response with a twist.
It's a preference for the rider, I have friends who love the thumb throtle and wouldn't switch for anything, as for myself being a motocross rider I love the twist throtle. Try them both and then decide you can always switch back if you don't like it.

 

I just bought a yamaha banshee and it had a twist on it. At first i couldn't jump or wheele or anything like that. I thought i had to change it for sure. But after a while i started to like it and learned to wheelie and jump as good as a thumb. If i were you and i got a twist i would get one of those things Jet skis have that when you fall off your quad turns off, because if you wreak and your quads twist gets stuck it could really mess it up by having it run with all the oil in the wrong places while it is running at full throttle. But i really like them better than thumb now, it just takes a little getting used to.

 

i don't think it will be ,much of a hard change for me because i had a dirt bike for about 2&1/2 years befor my blaster. And like bansheee king said i can always switch it back.