I'm not going to say which sound I prefer between the S80 or XV because they are both very good (but different sounding!) factory piano sounds.

The XV factory pianos are miles ahead of the JV sounds (but the JV1010's session board does indeed have a great piano sound!).

I also like the pianos in my Triton Piano expansion board.

Check out Kurzweil's new compact digital pianos- small, with alot of control and great sounds.

If the P80 does it for you then get it!

PS- Remember that you get a totally different impression playing piano sounds depending on whether it's an weighted keyboard or not! Cheers.