Main problem with generation gab is that Contax 645 is no longer made, or significantly supported. Yes DB's are still made that fit them but they camera is no longer made, you are stuck with the camera / lenses / accessories currently available. Yes they have Ziess designed lenses WITH AUTOFOCUS and a vertical grip, which would put it on par with the PhaseOne 645DF and Schnedier lenses, its older, less ideally designed for digital and again no longer made which I think is the biggest selling point.