That is very interesting what you said about the viewfinders. How much better do you think the Zeiss and Bessa ones are compared to the Leica? This is the first time I have heard this since everyone seems to rave about the M6s viewfinder.
Also, I wanted to reinforce how important build quality is. I was shooting my Mamiya RZ67 yesterday and ran into some issues. Yeah, they're well built cameras but I think I just have a finicky one haha. Man does it suck to run into problems with a camera in the middle of shooting. I almost raised the camera above my head before smashing it into the ground and then taking the sharp pieces of metal and plastic and pressing them into my eyes.