If history repeats the release of the next version of the S900 series won't be until Summer Namm 2011. The 500 series Clavinovas were just released recently and the S910 is equivalant to the TOTL Clavinova in sound set.

I could be wrong but I don't see a PSR trumping the Tyros 4 or the Clavinovas anytime soon. The sound engine in the S910 is ALREADY in a Clavinova 509!!