Perhaps things like sharpness, coatings, etc...being a matter of taste for most of us, isn't really "list-able" if I understand your question, however things like shody workmanship and poor engineering---the sort of stuff that is a waste of LF dollars(like, I understand, Tilt-all 4x5 holders) would be valuable things to avoid and might "make the list," if one were to be compiled. Of course anything included would be suspect since a contributor might not have the knowledge to evaluate something fairly, especially used equiptment. If I were to get a trashed Betax shutter, I might assume that all Betax shutters(maybe all Wolly shutters) are junk--which they aren't!. I might not take into account that I only paid six bucks at a yard sale (found it in a cigar box with Junior's Rock Collection)for the thing, or neglect to add that info to my gripe.----Cheers!