I've now got a couple of races and some reasonably long rides in on the XTC 29er 0. Overall it is a solid and well behaved platform that can really haul arse. The feeling of sitting "in" the bike rather than "on" the bike adds a level of stability when descending fast fire roads and comfort during long, sustained climbing. Both of these traits are valuable in quite a lot of the riding I enjoy. The frame is stiff and responsive so there is no perceptible loss of power when you stand up and put the power down. The front tracks true with the Overdrive 2 head tube junction and the Fox forks teaming up to keep you pointed where you aim. I am a big fan of the Fox forks and after messing around with pressures a bit I have it right where I want it. I use the lockout a bit but generally I don't feel the need. I love riding this bike.
It's not all roses though. I am really not a big fan of the Schwalbe Racing Ralph tyres. I know a lot of riders love them, I'm not one of them. They are OK but I think the side walls are too soft and that means I feel I need to run more pressure to compensate for the squirmy feel. Once that happens you lose some of the bump absorption and traction in loose surfaces. A tubeless kit may fix it but as yet I haven't put one in. Not a big fix but worth mentioning. The Avid brakes. Man those things squeal. The performance is fine, the set up is fine and I quite like the lever reach adjustment but the noise is just hard to ignore. There is also a 205mm rotor specced on the bike for this year and for me it is too much brake. I can see that for a bigger human there would be value in it as the increased stopping power would come into it's own. For my 70kg frame I really don't need it though. When I grab a handful of lever I often need to check that my fillings have stayed put after I have nose wheelied down the trail. I'm picky. Too much brake, sheesh.
The highlight for me is still the Shimano XT drive train. This stuff works. I love that even after 4 hours of slop and crap it keeps shifting with confidence. I am not known for my light shifting technique (read masher) and sometimes when I get tired (read after lap one usually) my gear choices are made rather late forcing a big jump in ratios and that disturbing crunching sound to emanate from the drive train. Even with that obvious disadvantage the XT doesn't complain and hits the gear allowing me to look like I might actually know how to ride a mountain bike. Love it.
So if wishes were fishes what would I do? First up Shimano XT Icetech brakes. No question there. Next would be some tyres and that would probably be Maxxis Ikons. I have one to try here right now but as yet it hasn't made it onto a bike. At 2.2 inch it would hopefully give a bit more volume and suppleness to the ride without saggy sidewalls. I have had great success with Maxxis as a brand but again this is a personal thing. After that it's a hard decision. While there is a case for lighter wheels it is a big expense when the stock wheels are solid with hubs that roll well and are easy to service. Get the wheels checked after a few rides and keep the tension right and they aren't too bad. If however Shimano ever gets it together and makes the XT wheelset with a 15mm hub I'll be all over them like white on rice.
As always, these thoughts are based on my personal preference and keeping in mind that I have 2 small children, a wife and a mortgage. I search out performance balanced with value and the XTC delivers both of these in spades.