All the FA ltds have it, though I'd say the one on the 43ltd is different from the 77 and 31.
The below are my personal opinion from my use of these 3 lenses.
Probably mostly made up in my deluded mind
The 31ltd seems special, that
extra smooth bokeh and wide FOV seems to give the subject isolation 'pop' that imo is better than say a FA35/2 even when both are shot at about the same f-stop and subject distance (eg. f2-2.5)
77ltd to me is more of a
blend of smooth bokeh, drawing, contrast , sharpness and longish focal length that makes the subject 'pop'
43ltd is different from the two. It
seems much sharper from wide open and stopped down and its 'pop'/magic seems to originate more from this than smooth bokeh like the other 2. Perhaps it gives the apparent impression that it draws the in focus subject far sharper than the OOF areas.
I find 43ltd to be a good walk around lens.
A bit on the tight FOV of things, but still very usable for walk arounds.
More like a 'tight normal' or a 'single subject / portrait orientated' walk about lens.