My 1956 Zorki 4 (engraved & lugs) is very smooth winding and rewinding. It sold me on the idea that the older ones are are maybe a little better built. All functions seem to work easily and accurately. I picked it up from "ostrovsky105" in the Bay for 30 bones with matching '56 J8. The high production numbers for Z4s & 4Ks make it easy to be picky until you find a good one.
I'd also have to agree, though I haven't owned one [yet], the Mir's trustworthy rep make them quite attractive as well. Despite the low production numbers, they still seem to be frequently available and I'm sure one in good shape can be found with a little patience and persistence.