I have upgraded to PDVD11. However, frankly I don't see the need after upgrading. Of course there is extra features, but that is only useful if you are utilizing it. In my case, no, I don't use any of the new features; and new features that I am looking for are not implemented.
PDVD strength is on movie playback, PDVD11 improves a bit on subtitle, movie quality wise is the same as PDVD10.
Music playback quality is not very good in PDVD10. PDVD11 has problem with music playback so still cannot compare. Lossless audio file is still not supported. Cyberlink is not focusing on music part.