I recently tested my old-new Leica M3 with a Summicron 50 f2 lens and I’ve been happy but not super happy. Happy because technically its sharp, doesn’t have any light leaks and the mechanism is cleans and smooth. Not super happy because I became a little sloppy with the test (took a whole month to shoot, very slow to develop etc) and hence the pictures are not spectacular with respect to composition or space.
If I was to just give out a few notes on the first experience, then I’d say that the best part about the camera is that its small, stable and spot on reliable. The bad part is that its heavy (100% metal body, something which is true with all premium cameras like the Hasselblad 500c or the 5dMKII), the double stroke shutter does sometimes take more than double stroke as you might miss winding it completely and focusing takes a little while to get used to.
With respect to comparison, I don’t think we can comment on the quality in terms of the photographs. Each camera has pros and cons and it excels in some spaces, it under-performs in others. And as it will grow closer to your heart, you’ll see it has a unique place in your workspace which no other camera can take. So if you like something, don’t think too much, go out and you’ll find a place for it.