spec wise? not huge, as i say at that price point its all very similar in performance, although in my opinion the GT is a little bit better, the drivetrain and brakes are marginally better, The frame Geometry on the GT is a bit better, head angle is a little slacker and wheelbase a little longer, which will be a benefit if you plan on riding more aggressively.
If its possible the only way to really know for sure is to get a quick feel on both if you are buying from a LBS, if ordering online its a gamble.
From my point of view i think i'd rather put my money on the GT.