I've got more than 38,000 miles on K60s now, with plenty of dirt, mud, and fast, twisty roads in the mix. Yeah, the front isn't as grabby as some full-on knobbies, but they have never washed out on me. I've been up to 118 mph (per GPS) without any unusual scariness, and have spent many, many hours at 70–75 mph on them. No other tire comes close to its versatility, and they last forever. I think it's the perfect match for the F800GS.
I'm tryin' ta think, but nuttin' happens!