I have about 3500 miles on my S4 so far (had it for 4 months now). It was my reentry bike, and I also had a Monster 620 that I ended up selling to my g/f because the S4 was so much more bike than the Duc. I find it to be a great compromise between sport bike and "naked" fighter. I commute most ever day on it (in LA), and it is waaay fun north of 6K. I've done one track day on it and it seemed perfeclty happy in that environment. I probably won't track it much as I'm much happier there on 4 wheels, but nice to have a bike that can do a bit of everything, and do it well. No maintenance issues yet. Very well built. That said, I might trade it for one of the 680 triples when they show up....mmmmm, triple.