Z3TA+2 is by far way better in sound quality than the original Z3TA, that one is a no brainer to me at least, however there were a few things they did away with like the built in analyzer which would be nice to still have.
Rapture Pro though is really just a face lift to the original Rapture, it's nice that it added Dimension Pro and Rapture together in one synth and the over all layout is a bit nicer but the main reason I went for it was there was a pre-order discount, or maybe it was an upgrade discount, either way I got it for almost 50% off.