Here's a quote from PSR Tutorial forum concerning problems with the PSRS910.
Was it released too soon? Is Yamaha in financial trouble because of it?
Of course I'm joking, but the quote and problem are real.

"Hello from Canada;
Four weeks ago tomorrow, I took my 910 back for repairs..... the operating system wouldn't boot up. Called them this week, (Yamaha), and was told that they had so many repairs in, that the technician hadn't even looked at it.
When me dealer heard that (Long & McQuaig), they immediately offered to just swap it for a new one, and when mine returns, they'll just put it on the floor for demos/tryouts. We did that; goes to show how important it is to deal with a reputable dealer."

DonM