I have an Audya, Roland E80, E50, and had a Yamaha S900 all sitting side by side in my office. Trust me, the Audya will make you want to throw rocks at the Yamaha, and as much as I like the Rolands, I don't turn them on since I got the Audya.
Only thing I prefer on the Yamaha is a few of the lead guitar sounds and some sax sounds. The Yamaha vocal harmonizer makes me want to gag, and the drums are not any better than Casio. But that's o.k. if you like them, or have gotten so used to them that they sound right to you. They seem to be the same drum sounds and the same harmonizer that debuted in the PSR8000 a dozen or so years ago.
As impatient as I am for the Audya upgrade to 4.0, I'm happy playing it as is. I don't recall Yamaha EVER coming up with a free improvement of any kind, as Ketron, Roland and Korg all have done.

The ironic thing is, Yamaha will probably be around when all the others are gone because they continue to allow us to pay for an entire new model every couple of years in order to get a few minor new things.
Of course these are just my opinions. They just happen to be right.
DonM