Faberryman hit the nail on the head in post #2.
I've owned a lot of medium format cameras including a 500cm, RZ67, Bronica S2a and Bronica EC. My favorite was the RZ but of course that is just me. When I owned the RZ I also owned a Pentax 645Nll for hand held shots out in the field. I was shooting people. Some do but I understand not wanting to carry an RZ around with several lenses.
While hauling the RZ around in the field is not exactly a FUN experience, it's not the impossible feat many make it out to be. I took my RZ with 50, 110 and 180 lenses down to Mexico City and shot on the street with it. All hand-held, no tripod. I even pulled off a hand-held shot with it looking straight up at the interior of the domed roof of the Palacio de Bellas Artes. IIRC it was Portra 400 - if not, Ektar 100, with an 1/8th of a second at f5.6. Tack-sharp, no motion blur. The weight can come in handy that way - keeps the camera super-stable even at slow speeds.