Zorki 6 of course.
It's a small, reliable camera, the long base rangefinder is pretty accurate, horzontal misaligment can be afdjusted from outside, it's easy to load (like a standard camera), the advance lever is made of chromed metal and has a nice feel (unlike the sheetmetal plate of the 4K),it has a dioptre adjustment, the shutter speeds are limited but they are 95% of what a photographer needs plus you don't fear to break down anything like the other SU models, the Soviets provide the camera with a complete system of high quality lenses based on pre-war Zeiss design but with a decent multicoating that help with flame...with little money you can have a Topogon like 28 mm (Orion 15), one of the 35mm ever made for rangefinders (Jupiter 12), a good Zeiss Sonnar (Jupiter 8), a fast 1.5mm 50 mm (Jupiter 3), an excellent portrait lens (Jupiter 9) and a decent long focus 135mm for outdoor shooting (Jupiter 11)...you can can get any of them for less than 250$.
The only real drawback is that you have to use the external turret if you don't shoot 50mm.
IMO it's also an aesthetically pleasing camera unlike some japanese ones.