I love the sunroof, even on a wet day the extra light in the cabin is great. The roof does need a bit of looking after though, I saw that Audi have a service for them involving cleaning, lubricating the mechanism and seals and of course checking the drain tubes. Leaks are most likely due to the drains getting blocked but are easy enough to check. I don't know about rattling as such but they do creak but again that is down to lubrication which is easy to do.
The other issue which I've had is with the plastic surround cracking but mostly this seems to affect TCRs and is a fitting issue at the factory. Mine was fixed and has been fine since.