"Keep up with anyone on the highway or in the twisties" (with that anemic engine and 21 inch front tire)?
The 1200 isn't really a fast bike, but IT
can be pushed fairly
well. Performance wise, the F800 is a dog on the road
, and (almost) everybody says so. It's not just me!
The F8 is narrower, but taller with much better ground clearence (can be lowered) Although it's still heavy by dirt bike standards, it's MUCH better in the rough stuff than the 1200. Some people do, but I wouldn't travel 4,000 mile/week like I do on the 1200.
I'm 6' 1" and only comfortable on the F8 for an hour or so, where the R12 is good for all day, every day. If you're going to be covering long distances, or strafing the twisties, you don't want an F800GS.
If you're comitted to longer stretches of dirt road (or rougher stuff) and not much highway it's the other way around.