That is a valuable point that really deserves more emphasis. I mentioned earlier that I tested a lot of these lenses over the past year. That was largely to check focus (and camera function). In the process I got to see a lot of side by side comparisions at proper focus (and used up a fair bit of film). More than half of the Rolleis I checked needed at least slight adjustment (which was done).
Originally Posted by rich815
I'd also add that nearly all of the old Tessars and Xenars I saw had at least slight haze on the surfaces in the air space between the first two elements (which I cleaned).
Because of all that (and more), casual observations about lens performance seem very unreliable to me.