The goal in street photography, at least the way I practice it, is to get the camera out of the way so I can just react to what I'm seeing this is why I bought a Leica in the first place.
So when shooting with an M4-P that means 28 or 35mm lens with Tri-X mostly but color sometimes, with the shutter speed at 250 or so and then moving the aperture as the light changes and using the distance scale. This has been the most successful method for me and I can do it unthinkingly and nail the exposure.
With a Ricoh GR-1, it's basically the same.
As I move to digital I try and duplicate this which is what got me to get an m9 and it works pretty much the same.
With my GRD3 which I use a lot, I wavier between using either shutter priority or aperture priority or increasingly manual mode.
Thing is that with film I can usually guess exposure pretty well, even with slide film, I don't really intuitively know how to expose digital to get it the way I like it. I feel like digital ISO is a lie. Exposures shot at ISO 800 at say 250 and f4.5 that would have been perfect on film are very underexposed on digital or at least on the GRD3.
Also I never ask for permission or do street portraits. To me, I need several elements in the scene to make viable for me as street photography, it's the interaction of people, light shadow and the city itself. But that's my personal bias.