Originally posted by bdery Build quality and MF are better on the M, but it lacks AF and is a worse optical performer. There is no reason for the M to be rated higher than the FA.
Are we talking f/1.7 or f/1.4? I have both 1.7s and would rate the M higher than the FA because of the build quality and handling, which together make it much more pleasurable to use. Optically there's no difference, and the M certainly gets a lot more use than the FA.
Like the 1.7s, the 1.4s also have the same optical construction, the only difference being possible changes in the coating over the years.
Beyond build and handling, price also has an impact on rating - a used FA costs more than double a used M, in the case of the 1.7 probably quadruple, so people will naturally take that into account.
I think it's fair for the Ms to rate higher than their FA equivalents. AF is handy but it detracts from the pleasure of taking photos, even if it allows some shots that wouldn't be possible with a manual focus lens.