...Ok I bit the bullet on Friday. I rode the piss out of it all weekend on the toughest trails we have here. A couple things. I'm not used to riding with clips on a mountain bike. I suppose I'll get used to it. Secondly, I find that the handlebars are way too wide. I was told this is normal on a 29er though. I clipped the ends a few times on some narrow parts of the trails. (and subsequently remembered I was clipped in a little too late)
All in all? I love it. It was between this and a cannondale but I went with the trek because I've always had treks. And because it has an extra gear. This thing is geared so low I can pedal fast and almost not even move!
Huge upgrade from my 6500...
You'll get used to the clipless pedals. Expect to fall a few times, so loosen the tension a bit. Also, whoever told you about 29er-specific handlebars, they were either yanking your chain or clueless. That's like saying you need a 29er saddle.
Anyway, nice Trek. One thing I like about Trek's is the warranty. Great service, from my past experience. One thing you should do is a tubeless conversion. Look up "Ghetto tubeless" on youtube. I did the gorilla tape version several years ago and it's been great. Split-tube method works well, too.