In my opinion, don't do it. I have a PA800 and I'm not upgrading. If you really want something newer and/or better save your money for the PA3X. See my posts on the Korg forum. Too many "professional" features were dropped to keep PA900 at a lower price point*. Plus there are the usual bugs and glitches associated with a green model.

As the public becomes better informed the market will be the ultimate judge. Unless Korg restores the missing chord recognition modes, addresses issues with the vocaliser, etc. in a massive OS update, five yrs from now the outgoing PA800 will command more than this PA900 on secondary market.

*I would like to add, the PA800 was better than perhaps it should have been. When introduced it offered new features that eclipsed the "top of the line" Pa1X. Within a year it was more mature and similar in capability to the PA2X (and that board was initially plagued by LED issues.) I'm sure it didn't take the marketing folks at Korg very long to realize they were cannibalizing sales of their high-profit TOTL models. They weren't about to make the same mistake this time around. Born in a weak economy, the PA900 was built to a lower price point. IMO it will never be as good. Some features might be restored in an OS update, but it will never have an EC5 connector, 4 outputs, improved bass response, etc. My $.02.