I'll add that - after having an M4-P, and then getting a Mamiya 6. The viewfinder in the Mamiya 6 is much bigger, better lit, and easier to focus frame lines.
I sold off the M4-P, after realizing the Leica lenses I lusted after were outside of my budget for 35mm film. Leica 21mm/ f1.4 ... mmm, so badly wanted that one. I then spent 3 years with Contax G2 kit, and found the Contax G Zeiss lenses were more suited to my taste, sharp, and really nice color renditions.
For a while I had both the Contax G2 and the Mamiya 6.
Then I went in on Canon L lenses - 35mm 1.4 L - whew, great lens and frankly between my Sigma DP2 Merrill and my 5DMKIII, I thought that my digital equipment was outperforming my 35mm analog gear. So it was time to move the Contax G2 kit, sadly I did just that, and I have left 35mm analog completely.
Not so with the Mamiya 6. It still out performs my digital equipment, so I bought a backup Mamiya 6. I have all 3 lenses, and I doubt I will sell the Mamiya 6, it really creates extraordinary images.
One other thing, not to troll, but I think there is a huge cult of perceived quality that Leica offers. I disagree, having peered into the innards of the Leica M4-P while it was being cleaned, lubricated and adjusted, it's nothing extraordinary - maybe the M3 is a different type of camera quality wise, but the innards of the M4-P were mostly dull steel and gears that looked grey and uninteresting - also they needed quite a bit of adjustment when I brought mine to Sherry krauter, she even replaced the viewfinder with a more contemporary one from Leica M7. Still after 6 months, of use, it was tedious for 35mm analog camera, and no expsoure metering built in. I swiched gears, and sourced out a Contax G2 with a full array of lenses and the 21mm Zeiss Biogon. The Contax G2 was much better made. So what are you really getting from a Leica, other than something to caress and covet ?
The lenses I suppose, that is, if you can afford the ones - that may offer something over their DSLR counterparts.
Yes I have heard all the claims - "marvelous craftsmanship", "iconic design" "small, covert - ideal street shooter". Meh, I keep one foot in the analog world for one reason, image quality. 120 roll film using Mamiya 6 lenses delivers much more detail, than just about anything I have shot, both digitally and analog. I don't covet cameras, they are tools, it makes about as much sense as someone drooling over a screw driver or a socket set.
If you are looking for image quality - the Mamiya rangefinders are at the top of my equipment list.
Ditch the Leica and get the Mamiya 7.