"Word of warning, some people like the rocket thumbies (sram thumbies) and some people prefer the shimano triggers.
Ergonomics works different for every person, so it's not a sure shot just cause someone else likes it"
Wow, I think that's about the best bit of advice I've seen from Jayem (just poking a little fun here). But he is dead right, everyone is different.
Personally I can jump back and forth between either style shifter and be happy using it in about 10 minutes. Though my preference is for the SRAM shifters, for exacty most of the reasons mentioned above, and the fact that I really like the X.0 rear derailleur. The shifts on the XT or XTR shift pods feel really dead to me to, there's just not a real noticeable click to let you know you did just fire off a shift. It is there, you just have to be really paying attention to notice it most of the time, and I'd rather concentrate on where my front tire is going.
And one other bit of info...
X.7/X.9/X.0 = 1 to 1 ratio
Attach/Rocket = 2 to 1 ratio
Just my .02, take as you will...