Hi, go for the Trek. It has better components. The GT has some very low-in-the-range Shimano parts and some no-name-brand parts. Oh, and those tektro brakes are not so great. Components are everything! When buying a bike, avoid things that will irritate you! Cheap parts will do just that! Go as high as you can in the Shimano range and you'll be happy. Your bike shop should be willing to change parts on the bike. XT parts, for example, are not so much more expensive than Deore parts, so you could upgrade before you buy, with minimal cost.
You should also seriously consider spending the extra money for hydraulic disc brakes. (Ask about Shimano Deore brakes.) I've had some problems with my disc brakes, but I would NEVER, NEVER go back to rim brakes. Rim brakes squeek and grate and make a black mess in the rain and rub and get mis-aligned and stop working in the wet and collect plant matter and need to be disconnected every time you take off your wheel and generally make you want to NOT RIDE. These are things that will irritate you!
Good luck to you.