Reading different posts and reviews over the years, it seems that lots of vintage scopes did not have a uniform level of quality in their optical performance. Everyone knows about the B&L's, but I remember reading about some unitrons did not perform well as others. The vintage C-8's were not consistent either. Meade seemed to be touch and go also.
But I do not recall hearing anything inconsistent about the Vixen brand of scopes, it seemed like maybe they had a better level of QC. Just something that I have thought about some, never heard bad things about Vixen, maybe some of you have other thoughts.