I'm having this same internal debate, except with the Mamiya 645AFDII and the Contax 645. I shoot with all nikon gear, some kodak, and rarely canon. 99% of my work is done with the Nikon D3. But after scanning in a few 100 slides, I've got the film bug.
I've been going out with the rolleicord (est. 1951) and am really enjoying the experience. But I'm borrowing this camera. I want to get my own 645 and possibly troll ebay and eventually get a db for it. after looking, I'm getting worried that if I get a contax, there wont be db for it. I'm also worried about if I get a mamiya, i will sorely miss the waste shooting since the prism doesn't come off. I'm really leaning towards the Contax cause everyone's reviews of it are glowing.
I really just want to get 1 MF camera that I can use and never have to ever buy another one ever again. With digital, in 7 years, I've bought D100 x2, D70, D2H, D2X, D3, and a kodak SLR/n.
advice?