Here's another one I've heard to avoid--lenses made by Carl Meyer. This was apparently an American company that sourced lenses from various manufacturers, some good, some bad. The name of the company was designed to create confusion with the venerable firm of Hugo Meyer, Goerlitz, which ended up in East Germany after WWII. I had not realized the ruse until someone pointed it out to me. Carl Meyer sold some very fast LF lenses, but apparently they are not very good.

One might say that Cosina is engaging in a similar scam with their "Voigtlander" line, but at least they are making good lenses. I just wish they would give them new names to avoid confusion with the old names like "Skopar," "Lanthar," and "Heliar," which have come to designate specific designs, and which are completely unrelated to the current lenses.