Pentax 6x7: great first medium format camera
The Pentax 6x7 (67) is a great first medium format camera because the glass is excellent and inexpensive. You will be able to collect a variety of focal lengths for well under the price of one Hasselblad portrait lens (another GREAT platform).
The P67 platform is also modular so you can start with an inexpensive 6x7 and work your way to the 67ii. The metered prism is my personal favorite meter. Plusses -- principally in the quality of image -- are too numerous to mention. There is even a Shift lens in the large lens catalog.
The camera's shortcomings -- mainly its awkward bulk and difficulty loading film -- are merely things most of us get used to. Diane Arbus shot this camera hand held and she was about 5 feet tall.
I also find that the mirror slap problem is mostly psychological. The mirror slap is LOUD! Humorously loud. Like closing the trunk of a 1962 Checker Cab. However, my bad shots are mostly from hand-shake because I've observed that the shutter goes before the mirror clatters home. (This is with Tri-X 320 or 400; I would use a tripod and mirror lock-up if I had 50 or 100 for landscape or architecture.)
A classic platform deserving of its longevity. My highest recommendation.