Hokay.. as someone mentioned Theres far to much sentiment involved and thus the mudslinging already started.. I think you’ll hear what you want to hear and believe what you feel like.. I’ll briefly list what components I have ridden (on my bike/s for long enough to have a opinion) and try give a unbiased opinion. SRAM X0 R-der (9sp) X0 Shifters(9sp) Juicy ultimate brakes Juicy 7 Shimano XT – 9sp XTR-9sp xt 2010 brakes Starting with shifting.. I found the major difference with shimano vs sram that sram was more rigid/harsh shifting.. this is where most of you get your SRAM raves from. This might mean better shifting in mud and SRAM is better at is shifting with dirty cables, HOWEVER this becomes really hard because the 2:1 ratio. So much so that on a long (70km muddy ride with cold fingers) it became so hard to shift I was afraid of braking the shifter) this was obviously intensified by the cold hands but the almost metal on metal feel of the sram shifters has its cons. I spent the vast majority of my rime on shimano riding xt rear deraleurs and SLX shifters.. these worked fine 90% of the time and as any drive train would with clean cables and fresh chain/cassette it was great. In this state I prefer it to the harsh feel of sram, but in the real world sram got my votes over xt because the accurate shifting through most conditions. Then one day I got chain suck because there was mud and grass in my cassette and SNAP! Sram Xo snapped couldn’t believe that a derailleur could snap from yes, cahinsuck, so be ware that theres a price you pay for the “quiet) sram r-derailleur’s, there’s far les movement which also makes wheels harder to install. So..I upgraded to XTR.. big difference.. I really think the heart of XTR is the shifters.. It has a bit more of the SRAM feel to it, but not the harshness. One can do multiple shifts from 3 different positions in either direction and Its much more robust than xt. Ive been riding it for 14 months now and Im still loving it, wont go back to sram If I can keep using XTR. It doesnt lose its settings in mud and it doesnt need babying as much. I have heard others go back to XTR after using stam xx.. interesting still not sure why..I would ride sram over shimano if I couldnt ride xtr and had the choice. I think shimano might age better as stam is quite highly strung with low tollerances and some serious metal on metal action, again the very reason it might perform better initially. as for chains and casettes, I found shimano last longer. I cant vouch for everything as I havent ridden XX or new 10 speed grouppo's but this is my humble opinion.. again.. biased as Im currently riding the xtr