Me too, I've had zero problems with my S900, which was actually one of the very early production models.

Having said that, there were a few reported problems here on SZ, which Yamaha took care of very well.

I always have a backup...if you play a lot, especially if you're a pro and gigging a lot, it's a good idea to have the spare.

Doesn't even have to be a keyboard failure...someone could knock it off the stand,or spill a drink in it...or it could even be stolen.

Ian