Somewhere I have a Contax 137 with a 50mm Planar lens, and I remember getting good results from it about a decade ago. Had a look for it last week, and instead, found a Konica Aiborg, and two Kiev 4 bodies. Even more surprising, I found my note book and discovered that I'd put a film through the Aiborg, but apart from my notes, I have no recollections of using it whatsoever, and it's such a strange beast.
Best recollections from 10 years ago - good results when testing a friend's Hasselblad 500C, it simply worked and delivered; - worst memories, the utter frustration trying to get a Rollei 6006 to work. Got it a new battery and 120 film holder/transport, and it was still unreliable most of the time, but very occasionally the stars were in the right position, and I had a few excellent transparencies.
Currently, I have film in a Retina IIIC, and in a Leica M6.