i once had an FS550 supermoto, REALLY fun bike, but fragile engine (main bearings went on me at around 60-70hours.
seems the next gen of engines (70? engines) were quite good and reliable.
friend of mine had a 570 (also supermoto) and thrashed that thing to the moon on tracks, street, and it never really gave in...
that's all i can tell you about the bergs
if you're looking for an offroader, go for the lighter engines...