As a Mamiya guy myself, consider if 1/500 is going to work for you? In the summer or otherwise bright days, 1/1000 is important to me (have a 1000s Mamiya), but I shoot wide open a lot, if you are landscaping this is not relevant or if it is relevant shoot 50 or 100 speed film and/or have a ND filter handy. You can't go wrong w a Mamiya 645, happy camper here (so long as you plan for the nuances).