The FA50/1.4 is very good on FF.
The idea that with new lenses out, old ones suddenly turn to mold is wrong anyway.
The newer lenses are generally sharper from wide open, but often, on the 'rules of thirds' area where most subjects are placed, the old lenses are fine/adequate as well.
The better central sharpness of the older lenses wrt the off center can also be used to emphasize the subject (say in a portrait).
FA50/1.4 @1.8
M50/2 at f8
The stopped down shooting in this use situation basically levels the field wrt newer lenses.
M50/2
Many portrait situations (esp on FF) are in fact not shot wide open. This one was a f4 probably for better DOF to all over more of the subject.
Indeed, as can be shown from the lenses used in the above picts, the portability of a lens is an undefined advantage that numbers based reviews can't show.