Quote Originally Posted by 02Pilot View Post
There are plenty of people, as even the most cursory search will show, who have had no significant issues in their use of Soviet LTM lenses. The limitations are well-known, and certainly they are not without some degree of risk (which can be mitigated by purchasing from a trusted source, as is the case for any used equipment), but they are not universally poor by any stretch of the imagination.
The big question is whether you believe (like Dante Stella) that the Soviet focusing helical dimensions were slightly different from Leica's, or (like Karen Nakamura) that it's just sample variation and a good Soviet lens is dimensioned correctly. It probably does make sense to do some testing of specific lenses with specific bodies in any case.

My own experience with them has been good, but the only Soviet lens I've used much on a Western body is the 50/2.8, where a slight difference wouldn't necessarily be obvious.