There are reasons to go for the Bronica. In the UK it is still half the price in all respects, whether it be kits or lenses. It is slightly smaller and lighter and arguably more solid (my opinion) and certainly ergonimically superior IMHO. The vertical orientation suits people and place photography just as well as the horizontal, but admitedly not landscapes so well. If there is a lot going on 16 frames gives you less time changing films and the integral darkslide thingy is a big improvemnt over the Mamiya. 645 gives you the chance to show grain too, using fast films. 6x7 is going to look creamier, which might not be what you want for street photography
I would seriously consider one for travel/reportage. Most shots would be mono and printed to moderate sizes only and as many would be vertical shots as horizontal. For the price of a M7 plus 50mm plus 150, you can get RF645 plus 45 plus 100 plus flash, filters etc plus a great used 5x4 outfit! I love the idea of the M7 but I think the lenses are crazy money. Perhaps the RF645 could be characterised as leaning towards reportage and the M7 towards landscape?