I should add two things (1) OAA is Open Art Arranger, software-only add on that you can buy (I think it's around $1000) that lets the Wersi OAS play Yamaha (and other) styles directly. I have not tried/used it, but have read good things about it - $1000 though, to have your Wersi play Yamaha styles?!

Also - the Wersi makes a great MIDI master controller! Love the feel of its keyboards. We use it to control the Artisan plus a Roland Fantom. We do layer in some Wersi sounds, and the combination of these three is quite fantastic in sound, esp. playing orchestral music or classical organ music. When I want to play using styles, I move over to the Tyros or S900 or KN7000 though.

Jim