i have the f800gs. i love it. i've done some offroading with it, too.
dollar for dollar, there are better bikes out there. the triumph looks like a better bike, when you factor in money. i like the larger power output and the excel rims. i just bought a second set of excel rims for my bike, jeez!!!
hell, the f650gs twin is a better bike, again money as a factor. there's nothing the f800gs can do that the f650gs twin can't do. the only difference is the extra $$$ in your pocket.
i love my GS, though!