The Leica brings back memories of my first real camera, a Argus C-3 rangefinder bought new back in the early 1960's at Talls Camera in Burien (Seattle). I used it with a external light meter. I generally used Kodachrome slide film rather than print film. I used the C3 all thru the time I was in college, and for a couple of years afterword. My first 35mm SLR was a Canon FTQL in about 1969, and built a darkroom in the garage of my first house in 1967. I mostly developed B&W film, when I tried developing ektrachrome slide film, I often got a slight blue-green tinge. I also dabbled with color printing, but after the first child came along, we moved to a larger house, and I had other priorities and no longer had a darkroom.
There is little question in my mind that a range finder camera is a unique experience, and produces excellent sharp images with little effort. You do not have that big mirror banging up and down, not the large focal plane shutter, just a tiny click from the diaphram shutter built in to the body, and then the huge pop and flash from those press 25 bulbs.
Of course, you also did not get the advantage of thru the lens viewing, or the built-in light meter. You were able to exchange lenses, but it was never something I was interested in trying.