if you are doing more aggressive riding, the hardrock pro is a pretty good choice. Its more of a downhillerish/dropoff/aggressive XC, but its weak in some areas. I was so close to buying one. The bike's Geometry is real nice for more aggressive stuff but is not nice for uphills. The bike is fairly heavy however you have a good amount of strength in many parts of the bike. Its a forgiving geometry if you are the type of person that does stuff on a bike that you might not have the skill to do (ie dumb and crazy like me). a couple of things that made me not buy that bike but to buy a Specialized P2 (more of a dirt jump/urbanassult type bike) were:
The breaks: good breaks but entry level and didn't have all the stop i needed
The fork: Since i broke the fork on my P2 in five rides (upgraded to a DJIII) i would be carefull of that
the shifters and deraillers: worked good but i was scared they might not last.
Don't get me wrong for the money that is an amazing bike. If you aren't super hard on your bikes like I am it would probably be fine. I do alot of dirt jumping (5' jumps), lots of drops (up to 9-10 feet), lots of urban riding, and lots of downhillish XC riding and log rides. all of that stuff really is tough on a bike. IF you are just getting into biking i wouldn't worry about breaking the hardrock pro (i've been biking for over ten years) it would put up with the abuse of even a crazy first time rider (it has some decent rims and a solid frame). It probably won't handle more than 5 foot drops, and rough jumping on a regular bases (unless you are lite). Also its not a 100% XC bike, its a close cousin to the P2 which is an urban assualt bike. This bike i would say would be for a begineer to intermedate rider that is harder than most on bikes but not ruthless. If you want a easy pedalling XC bike this is not it either... go for a gary fisher or something (maybe a low end rockhopper... don't be hung up on the disc breaks they work about the same as a rim break in most conditions). I personally would stay away from GT stuff (just my opionion).