I tried to like the Contax 645 (45/80/140) hard, really hard, but I didn't manage. Thought it would give me Contax G like quality in medium format. Somehow it didn't. Maybe it was the rendering in b&w, or the form factor, the abundance of electronics, the fear of breaking it and not being able to get it repaired with Contax RIP; I don't know. The whole thing made me nervous. So for no better reason than that I sold it. Freedom regained.
It was a good experience though. I learned to reappreciate my Contax G1 and my Rolleiflex. I learned that 6x4.5 isn't for me. I learned that what is good and what is not good isn't something to ask another person; one has to try for oneself in order to know. Maybe I simply learned that there are no good systems and no bad systems (except for the really good ones, and the really bad ones ).
About the 80: it's probably at its best in colour, and not at its best in contre-jour sort of situations. Focusing at f/2 can be tricky, and that's an understatement. I would have been happier with a less flare prone 80/2.8, but then there are other systems that can do that same trick. The 80/2 does have 'character'. It's one of those lenses that you can pick out on flickr without reading a single letter.
I can see how people love the Contax 645 system. To the OP: I love the top four samples. Seems like the camera is in good hands!