For many people (of course me included) the Contax is a cult object. My obsession started when I was 15 y.o. and I got my first one at 52. There was a mid time training in using a Contax when I bought a Kiev 4 in 1982, but even being almost the same camera, it wasn´t the real thing. Anyway, being myself at that time an SLR shooter, the Kiev gained the position of my favourite camera disregarding the Contax grip, the slow knob winding, and the speed selection which IMO are by far the most uncomfortable features the Contax had.
Mine is a II from 1937 with a collapsible Tessar 2.8 50 mm, of which I was in doubt of being the best lens choice (to be honest I was looking for a Sonnar 2/50 or 1.5/50). The camera had the shutter defective, fogged RF, about 70 years of dirt inside and out, self timer jammed, lots of Zeiss bumps, and the chrome in the lens barrel was partially worn off. No doubt signs of extensive use. I´ve just payed USD 50 for it, so no complaints after seeing the asking price for others which were from USD 700 to 1250, both cameras fitted with Sonnars.
It took me about two months of patient restoring work, but now everything it´s OK (but the self timer).
Once the first shots came from the lab, no more doubts about the lens nor the camera. The most important thing I can say about the Contax design is that after 70 years, the shutter accuracy is still good (I don´t know if the ribbons were replaced or not). The only I have to remember is to extend the lens before shooting.
Now I´m looking for another Contax II but this time with a Sonnar 2. For the asking price it has, I can imagine another time for restoring practices.
No doubt they are excellent cameras, and they were one of the two best cameras of their time.
Go for the Kiev, it´s an excellent camera, and a good pre Contax training. Later you can raise the funds for a Contax.
Good luck.
Ernesto