SRAM is cheaper which is why I think they are coming stock on more bikes. Makes it nice if you are a serious mountain biker because it is not if but when you will need to replace parts. That is especially true is rocky, dusty Texas. My bike shop also said they have a way easier time resolving any warranty issues with SRAM. I personally like the thumb shifting only, it seems to be more intuitive to me. I am running X7/X9 combo on my Epic and have no problems. Now if I had a choice of Avid Elixirs or something else I probably would go with something else. I think there are better brake manufacturers out there.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan