A couple thoughts...
...regarding Lance's comment... from what I understand of the new XX drivetrain, it is essentially set up like a road bike's drivetrain 2 chainrings, 10 cogs. The idea is that you get less overlap in gear ratios. It would make sense that a roadie would really like this setup. Although my main riding is offroad, I think the weight savings and closer gearing has convinced me to move to XX when it is financially feasible -- that is, when I find a way to justify it to my fiance
...speaking of road gruppos... to comment on SRAM vs. Shimano, I'll throw another comparison for perspective. Dura Ace, Shimano's higest end road kit (specifically shifters, crank, chain, and derailleurs), is a bit heavier than SRAM's highest end kit, SRAM Red. We had a meeting with a SRAM rep here at my shop, and while it was definitely a pep rally for SRAM, one thing that stood out to me is that SRAM's shifter use less than half the moving parts of Shimano's. Arguably, this accounts for less weight, and potentially, less break downs.
...now back to off road... I am definitely SRAM biased (X.0 rear, X.0 shifters, 990 chain, 990 cassette), with the exception of the front Der, where I run XTR. I've played with several bikes here at the shop with different setups, and I've done quite a bit of research, and this is what seemed to be the ideal setup for my style of riding.
But then how does everyone define "crisp shifting?"
In most cases, if you are really comfortable with how your chosen setup works, you know exactly where (in your shifter actuation) your gears will change - With my bike, I know that the gears will switch when I upshift when I release the up shifter after it clicks. When I downshift I push in the paddle, and I can almost sense the cable sliding and then there is a barely perceptible click and then the shift happens. IMNSHO it really boils down to a feel preference... until someone comes up with an armor-plated rear derailleur with a cow catcher, that is...