Only Yamaha styles can be played directly.
The rest are converted, however because Wersi has full control of the conversion process, you get a more superior conversion compared to the software on a computer. (It is however still a conversion, just a better conversion them normal)
Diki
Are you now saying that overnight all Yamaha boards now have a full live sound and have dropped the compressed CD quality sound, so that they now sound as live as Roland, Korg, Ketron, Wersi etc, if so, then yes, the Wersi voices will not be any better then on a Yamaha, but somehow I don’t think Yamaha has changed their sound system overnight.
Mega voices: Wersi have their own equivalents, which operate identically to the Yamaha Mega voices, and can also be edited.
SA voices cannot be used in styles on a Yamaha; however there are as good and better voices available via VSTs, and all these can be used in any of the styles on a Wersi.
Hope this clears a few things up
BTW do a search on SZ and you will find plenty of sound demos and videos of Yamaha styles played on a Wersi. (Also do a web search)
Regards

Bill