I frequently use vintage lenses on m4/3 cameras.
Although I occasionally use a zoom, I prefer primes and sometimes carry two bodies for the obvious reason that it is not always convenient or maybe even possible to swap lenses out when shooting on the street. For me, more often than not a 50mm is my "wide" and a medium tele like a 105mm is my long lens. For a lot of street shooting both give me the longer reach that I prefer due to the slightly longer lenses and cropped sensor. And I might carry an actual wide angle in my bag just in case I want a building or landscape shot as well as with these there is time to change out the lens.
I am using a Panasonic GX-7 and an Olympus OM D EM 5. No particular reason for picking these cameras specifically except they were available second hand in nice condition, at the right price, at the time I was in the market and are both in their own way well specified. The Panasonic has focus peaking which can be useful in the right circumstances, but the Olympus has better (sensor-based) 5 axis image stabilization which is also of value when shooting in poor light at slow shutter speeds. These cameras complement each other quite well due to their slightly different spec and handling.
BTW in relation to zoom or prime, though old vintage zooms are sometimes a little compromised image quality wise (though this is often overstated with any zooms I have tried) the main reasons I prefer to use primes are (a) their small size and (b) most importantly for me, they are faster and hence have narrower DOF (which I prefer) and can function better in poor light.
