Ok, that's provocative, but:
I recently met up for an afternoon with a very high end art photographer who swore that for his purposes (lets dumbly call it "walk around photography") the P65+ was far the better back - less color casts, less fussy about light entry angles, MUCH longer battery life, etc.
Both he and I were on Alpa TC's with IQ180's, and we both miss our P65+ backs, and kind of wish we hadn't traded up.
Then I had some emails with yet another high end art photographers (I'm talking about people who have major international museum shows) who also uses Alpa/Phase, and says the same thing: life was easier with the P65+.
That makes 3 of us. I see a pattern!
(I guess one point being: if you are looking for great used back and work with a technical camera: look hard at a P65+)