It is common to think of older cameras as "more MFDB" or "less MFDB" compatible, depending on whether they:
A. Have CPU contacts to communicate with their film back, hence the MFDB uses the same contacts (which makes MFDB with the camera communication easier and "internal").
B. Need cocking of the shutter or not…
The Contax (and the Rollei) fulfils the above, IMO, this kind of communication is all an MFDB user will ever need, more than that, (as Hasselblad or Mamyia do - especially Hassy) makes the system more prone to bags and other software problems that are extra sources that can affect reliability. I'm personally a man that doesn't like to change equipment or to upgrade often as others do… whenever I have to make a major decision, it's a careful and well thought one… I'm stuck with Nikon FF for 33 years now and many of my lenses are AI-S bought from new, I was with Bronica for MF for 20 years and had a great 10 lens system, the reason I changed to Contax, was purely because of the "digital revolution" and its compatibility with it, my MFDB is a 16x multishot capable one, with "only" 22mp resolution for single shot, yet, I find that (combined with my Contax lenses) it beats my D800E for anything as far as "single-shot" is concerned, I find no significant or valuable reason that a higher resolution/modern MFDB does anything better in single-shot (well it does, but not significant (or to the extend) to affect the quality or print size of my photography) and it provides me with what is better image quality by a million years than any of todays 80mp MFDB when it shoots in 16x (most of its use - proffession).
Never the less, if I was a starter, wanted to fully explore MF and its values, share the knowledge I now have in photography and respected my income more than my ability to spend (as I currently do), I would buy a couple of Bronica ETRSi bodies, a 40, 60, 100m and 150 (PS version) lenses, with a handgrip and three VFs (WLF, rotary and pentaprism), a double stroke grip and 3 screens for "peanuts" (1000 or so) and an Imacon 132c (with Bronica plate fitted - yes they did make it) to go along with it… and I would work professionally, being as capable as with any other camera!
P.S. Has anyone (one that prints huge and REALLY masters the technique and profiles of printing) ever tried to do a 36ppi print out of well shot and processed 22mp fat-pixel "magic" Kodak sensor 10years old MFDB??? …Wait until you try a 33 mp Dalsa one!