Each type of camera has its own strengths and weaknesses.
The type of photography some people do may be narrow in scope and this may lead them to believe the camera they use in their type of photography is suitable for other people in a different area of photography.
Thus we have highly subjective claims of format superiority or camera type superiority.
While there are certainly differences in the rendering of lenses with similar focal lengths and maximum aperture, exposure, film, developer, paper choice and print style is the most obvious feature. My three favourite 50mm lenses are the Helios 103, Pre-AI Nikon 50mm f2, and the Yashica 50mm f2. These would not be on most people's wanted list, and I own more valuable glass, but they fulfil my purposes and dictate camera choice.
Unfortunately the Helios is limited to vintage rangefinder cameras I can't rely on as daily users, so while it's probably the most attractive for some situations, use is restricted by camera technology. The Nikon 50 f2 (aka Japanese Biotar) is widely acknowledged as a uniquely good draw and a beautifully made lens, and it obviously fits early Nikons best. The Yashica ML 50 f2 is a lens I always thought was a personal quirk of my own, and I'd either got an exceptional copy or was imagining things that weren't there - easy to do with lenses. Only recently I've heard this appreciation echoed on podcasts, with one claiming it was identical to Zeiss in construction and glass type. Whatever the truth, it's the most "German" rendering of any Japanese lens I've used, very sharp, great tonality and a genuine sleeper. The lens is my go to 50, no question and I sincerely hope the prices don't rise from the £25-35 they currently sell for, sometimes with body.
I've owned a Leica (M5) and used a borrowed M3 and they are indeed very nice cameras, but I'd need convincing the lenses offered me something more than I currently get. For compactness I generally go for the Olympus XA3.