Epu- I don't agree about the guitars! The XV guitars are much better than the JV's (even though the JV's guitars are still very good!). I love the way you can use velocity to realistically imitate 'bending'- it is so realistic and as a matter of fact I'd go to say that these are the most realistic guitar sounds this side of an actual sampler! Even better than the Kurzweil K series guitars.
The strings, pianos, electric pianos, brass and drums are also much better than in the JV's. However, I still can't help for more variety in the drums department (like in my Korg Triton!). I suppose that is where the new drum expansion board comes into it!
The pianos in the XV put the JV pianos to shame and you would need the sessions expansion piano sound to get anything as good in the JV synthes (the JV1010 already has this built in!).
The strings are much better but still aren't as responsive and realistic as those in my Korg Triton and TR Rack. I will get the orchestral 11 expansion board for this.
However, the JV's are still great sounding synthes (that's why I'm keeping 1 of my JV1080's- I sold the other one to put money towards an XV3080).