I had a Mamiya 6 for many years. As you state, the lens quality is excellent. However, i eventually sold it as the hasselblad system is all I need, and perfectly adapted to the way i shoot. I liked the Mamiya system a lot, and believe it is one of the best systems out there, but is VERY fragile. The winders are the things that go, and spares are not available. If the gears strip, you are done.. The usual recourse is to find another body, or your lenses are useless.. For me, it was a no brainer switching back to the hasselblad. I liked the lightness of the Mamiya, but it did not work for all scenarios, like close-ups, and i preferred the SLR for ease of composition in the cases. Hasselblad also has tons of spares and parts available, whereas the Mamiya doesn't.