There is the problem with the stepper motor acting up if you ride in a lot of dust, if you google it, there is a bit on it (800Xc). There are ways of preventing it, just cant remember what though as I have the Xcx and those dont suffer the same problem.
The main air filter is s bit of a mission to get to, but I put on a pre-filter so I just keep that clean and oiled.
Other than that, nothing I can think of. They are great bike, sound great and you cant go wrong.