My combination of Soviet lenses with a classic German Leica IIIa has worked out pretty well; I am expecting it will be more successful than the infamous 1939 German-Soviet Pact which lasted just over a year.
The Industar 22 and the Jupiter 12 lenses seem to be performing equally well, though I have mostly shot them so far in bright light conditions and at small apertures.
The last roll of film I put through the camera was Kentmere 100 which I processed in Rodinal at 1:50 dilution. I'm looking forward to trying some other films and developers, including some PMK Pyro.
I have ordered a replacement beam-splitter mirror for the Leica. It turns out that the mirror coatings used on the Soviet Leica copies was actually superior to that used by Leitz in the Barnack-style cameras, and my IIIa has no better rf contrast than most of my other cameras from the same era. If the surgery goes as hoped I'm expecting I'll have more confidence in using the Leica in low light, and that should provide a more significant challenge for the German-Soviet alliance.
I check the lens listings on ebay every once in a while, but the chances of finding a good Leica lens at a reasonable price remain slim. In any case, I'm happy enough with the experience so far, and it is nice to have an excuse to get back to using all my rangefinder cameras more.