I think trading slow speeds for reliability is a good call. The FED/Zorki cameras all, as far as I know, have similar fast-speed shutter mechanisms that are reasonably simple, and there are multiple sets of repair instructions online---the slow-speed escapements seem to be where most of the complexity is and where serious problems are most likely. That criterion would militate for a FED-2, Mir, or Zorki-6 if you can find one (+FED-1 or Zorki-1 if you don't mind the separate rangefinder window and bottom loading).

I have a FED-2 and a Mir, and they're pretty similar in form factor. I wouldn't quite call either one pocketable unless your pockets are very large, but the weight on a strap is nothing to be concerned about. The FED has a longer rangefinder base, but otherwise the two are very, very similar cameras functionally. They do have that "Soviet-industrial" feel about them, as if they might have been made in a converted tractor factory, and that bothers some people---I find it sort of likable.

Somewhere, I found little adhesive rings of soft material that fit over the eyepiece---before that, they scratched my glasses to hell. I think all the fSU Leica-mount cameras have this problem. Unfortunately I can't remember now what the source of the rings was.