Great side by side comparison! Sorry I haven't read the other responses but I'd say the Audya sounds best.

Audya drums, and percusiion kill the Yamaha- hands down. No comparison. Korgs drums and percussion was not as good as Audya, but much better than Yamaha.

The Yamaha Latin percussion especially guiro and cha-cha cowells sound very fake. Korgs drums and percussion were second best. Really the Yamaha percussion (not drums) sounded bad.

Horns sounded best to me on the Yamaha, a very close second on Audya, and a destant third on Korg.

I only listened once, and as far as piano, bass, and other instruments on the SMF, none of the keyboards seem to have a clearly better sound. I'd say a tie.