A bit more time with the 645Z and here are the key points, all of which are subjective so test one yourselves-
- The AF is quick and accurate.
- The sensor is amazing and handles just about any subject well.
- The camera is responsive and has very little lag.
- The viewfinder is amazing.
- The 55mm lens is sharp across the image at f2.8
- Its well built.
- The menu system is complex.
- It has too many options.
- Too many external buttons.
- Its ugly.
Most of the gripes with this camera are minor but could become major if you used it every day, as a wedding, location and possibly product camera the 645Z would be a great addition to the arsenal. I could see this camera doing editorial and reportage in a pinch as well. I think the major drawback for it is the focal plane shutter, if you are shooting flash you need the faster shutter speeds of the lens mounted shutters.
There will always be those who want the ultimate lens quality coupled with simplicity and image fidelity of Hasselblad but there will also be another camp who want medium format at a price point, and there is nothing wrong with that as we have something to cater to both camps.