Vlad, you could do better interviewing Zoom, or me:-)
Most 'party' (Communist Party that is), or official photographers used foreign equipment. Some of them traveled abroad and bought it there, some got their cameras through other channels. This was the top tier of photographers, those who got published in magazines, newspapers, etc.
But "second" tier photographers (street work, local newspapers, weddings, etc) did use Soviet cameras, not by choice, but this is what they could get. Medium format was a pro choice, and Moskva and Salyut were two top models - this is something I witnessed myself.
Kiev rangefinders were the most common 35mm cameras.
I actually belonged to this second (more like third) tier, and used Zenit-E most of the time. It worked, but if I was shooting alone, I always needed a second body, since Zenit could break without warning at any moment). Since I could not afford having it, I would borrow it from other.
The film: There were two common film brands - Svema (Shostka, Ukraine), and Tasma (Kazan, Russia). We preferred Svema - it was a very good film, especially slow one, GOST 32 and 65 (about the same in ISO).
Soviet-made color film was bad, we tried to find ORWO (East German), which was OK, and their slide film quite good.
<<In stores he said the Soviet cameras were freely available at the time, and only amateurs would buy it. These cameras cost a lot at the time and he said for such high price you would get very unreliable pieces. >>
I want to elaborate here. yes, some cameras were freely available, but either outrageusly complex and expensive (Kiev-15) or crap, like Shkol'nik or Smena.
Anything in between, that people actually wanted - good inexpensive cameras like Zenit-E, FED-5 - were almost impossible to find.
Speaking about interviews - this one is with me:-). Some 10 years ago.
http://home.cfl.rr.com/lenswerks/new_page_91.htm