im thinking about getting a new bike, and currently i have a trek 3700. I ride this bike very hard and it takes a beating, and i was thinking about upgrading to a trek 4500 with comp. disk, or either a specialized hardrock with comp. disk. I wanted to get an opinion on which bike would be the better bike to have when riding long rugged trails and doing a little bit of dirt jumping. Only about 5ft tall at the most. So i would appreciate it if i could get some sugguestions.