Based on my experience it depends on the component. XT BB spindles are significantly better than LX, Deore, etc, Deore Crank sets are fine, LX rear derailures work & last as well as XT. However, I've only been satisfied with XTR front deraillures. Even the new XT design, which looks like an XTR, doesn't do it for me. Deore f derailleurs just falls apart and won't hold adjustments if you ride a lot (same happened on my wife's mountain bike).
I really enjoy my XTR shifter pods, but only because I got them and my wife's XT's at a very cheap package price from a shop owner who wanted SRAM for his bikes. LX pods seemed OK on my wif's road bike. Deore pods aren't too bad either, but they get kind of imprecise with a lot of use rather quickly.