What is nice about the Contax is that you can use the Zeiss Ikon film cassette, and it eliminates the need to rewind, although you probably should unload the film in a darkroom or camera bag.

The Zeiss Ikon film cassette can be used in many Zeiss Ikon cameras: All Contax models, Contarex, Super Nettel, Nettax (35mm rangefinder), Tenax II and all of the Contaflex models. In the early days of eBay, you could buy these quite cheaply (less than $10, as I recall).

I think that you'll find that the Contax I, properly serviced, is a fine camera. There are some shortcomings: two viewfinders, a very tiny rewind knob and sort of a quirky way to advance the film and tension the shutter.

However, I think the shutter release is about perfect. And Zeiss Ikon, at the time, liked to point out that there were no spinning dials when the shutter was released - a clear shot at Leica.