In one of those strange coincidences that comes along from time to time, I also recently got rid of my R1200GS and bought a KTM 950 Adventure S, almost exactly like Tobers' bike. His looks in better condition cosmetically than mine though
To sum up the difference between the GS and the KTM, I'd say the GS is more refined, and definitely a better road bike. The KTM will probably cope with hard off road use far better, which is why I bought it. The KTM uses far more "standard" technology, so is far easier and (hopefully) cheaper to fix when something does go wrong.
But I'm still missing the fantastic handling of the telelever (on the road!).