I have the Bronica RF645 with 65 and 100mm lenses. Before I got it, I borrowed a Mamiya 7 with the 80mm for a few days. Especially with a lens mounted, the Bronica is much smaller and I found it to handled better. I thought the 65mm was the best medium format lens I have ever used (and I've used many). It's sharper and smoother bokeh than the Mamiya 80mm. The Bronica 65mm is sharper when looking at the negative, but not enough sharper to make up for the larger negative, but plenty sharp enough to make a great 16x20 which is as big as I ever print.
One main reason I bought the camera was for travel and walking around all day so the smaller size and more shots per roll were a great advantage. I do have a 6x7 SLR (Bronica GS-1) with a bunch of lenses for when camera size doesn't matter. I might have made a different choice for an only medium format camera.