Although I mainly use Pentax, I have had a Contax 167MT for the last ten years. It is a very solid and reliable camera and in tests by various camera mags that I have read it & the Carl Zeiss designed 50mm f1.7 & f1.4 lenses have often been very highly praised. Mine has the f1.7 and I have found it excellent.
I have no experience of the Leicas although aware of their high reputation. I would think that because the Contax winder is integral, it would be less cumbersome to hold than a Leica (or any other camera) with a bolt-on winder.