I think I can chime in here.
I have an 09 wrx(stage2) and I just bought the wife a MY11 dsg gti.
IMO the gti is "better" in only a few ways, and even they are questionable.
The gti has a nicer looking and feeling interior and the stereo sounds much better, but the wrx has easier to use controls and I find the seats in the wrx to be more comfortable.
The gti has better fuel economy but this is mainly due to the granny forced dsg gear shifts. I bet if you drive it hardish the gti isn't that much better on gas...
I have 45,000+ km on the wrx and the car has had no problems that required a dealer visit. For less than 2 grand I upgraded the downpipe, exhaust, intercooler, bypass valve, tune, bushings and swaybars.
Dan