I have a Mamiya 645 super and a few lenses. Lovely camera and also very forgiving when you take it outside into the landscape, and it gets rained on, and hailed on, and blown at, and sand _everywhere_.
Recently I have had the light sealing replaced, and the camera serviced, and everything is working perfectly again (touch wood!).
Somebody once told me that Bronica's are not as happy to go on an outdoor photo shoot, but I'm not sure this is true. I have no experience with that camera, but I've heard the lenses are very good.
All this assuming that you would want to take your camera outdoors.
Good luck making your choice. The step up to MF is a great adventure.