Of all the classic 35mm cameras I have tried over the past seven years, I can say that there are at least eight or ten that I really love. And any of those eight or ten would be good enough to shoot as my only camera. I can't say the same about medium format cameras. Haven't shot one up to this point that I'd put an exclamation point after.
My first MF was the Mamiya 645Pro. I actually liked this camera a lot when I was just fooling around with it in my house and yard. One day, however, I took it out for a day of shooting. By sundown, my neck and back were sore from lugging this behemoth around. There's nothing to complain about with the camera itself or Mamiya's fine lenses. This camera is just not meant for street shooting, hiking or even just walking around. It was designed for wedding photographers and studio work; areas where it excels.
Next up was a Rolleicord I inherited from a friend. Fine camera. Superb lens. I had never shot a twin lens reflex camera before. And because this camera had sentimental value, I wanted to love it. I didn't warm to the Rollei. It was fiddly and I found myself always using the magnifying eyepiece trying to get my shot into precise focus. Bending my head over to look down into the eyepiece and then looking up again aggravated my vertigo (a condition I have suffered with for years). It's bad enough I'm old and shooting an ancient looking camera. I really looked funny stumbling around with dizziness after focusing.
Next up were two rounds of Hasselblad 500-series cameras. To eliminate the viewfinder issue described above, I tried various versions of pentaprism finders for the Blads. The one I liked the best with built in metering was huge and heavy, turning the 500c/m camera into almost a Mamiya 645Pro. Again, the Hasselblad is a beautiful camera and the Carl Zeiss lenses will blow you away. And I loved the removable film backs. The Hasselblads just weren't my cup of tea.
I had almost resigned myself to being content as a 35mm shooter when a friend sent me an email and asked if I'd like to try the Pentax 645n. He had a nice, lightly used one for sale complete with 120 insert and SMC FA 75mm f/2.8 lens. We made a deal and I traded my Mamiya for the Pentax.