Contax bodies are great when they work; my first camera was a Yashica FX-D (poor mans 139) and a 50 1.4 Planar (loaned to me from my father when I was 8 years old)

OTOH, Nikon bodies are way more reliable and the Planar may have been updated in the ZF configuration and thus "better"

Going with C/Y cameras does open you up to the entire C/Y catalog