Thanks everyone for all your opinions. I've been reading and taking note but counter to the general consensus I will most likely get the 645DF. Even if it is not the best body out there it just seems the best choice in my circumstance for upgrading later. Another thing that I think will be interesting to see is the new body coming out which Phase One has said they're working on. If that turns out to be nice I will kick myself for not purchasing a Mamiya mount back now.
Michael Reichman doesn't seem to complain about his 645DF either, I think I'm in a win win situation. Either system will do what I want it to.