I think the Rev2 is great. I bought the 8-voice then got a Prologue 16 to play alongside it. Then I realised having 16 voices was important and got the upgrade for it.

I am very happy with it, but I guess it depends on what you do. I'm a player and the 5 octave keyboard is really essential for a poly. That's the main reason I never considered the P6 or OB6.

As for hardware vs software, same thing really: for playing, hw is essential. I guess if you are mistly midi sequencing, it might not matter.