I have recently picked up a Mir-10A from a flea market for very little money. It is a 28mm f3.5 preset lens, m42 mount, very heavy with 67mm filter ring, and focus down to 0.2m.
Must admit I was surprised by its performance, while much more cumbersome compared to the compact 28mm f2.8 on my OM and PK cameras, it seems to excel in rendering an atmospheric image; I documented a left-wing rally with this lens and somehow I felt it captured the tension on the day.
I want to find out more about this lens, there isn't much information out there on the net. Perhaps finally there is an proletarian answer to the mythical "Leica look"?