I have both and I don't use the FA 77, but then again, I don't do many "portrait sessions." My wife uses the FA 77 quite a bit and likes it a lot. It is just that on APS-C, the FA 77 seems kind of long. It isn't the fastest focusing lens, so even though its aperture should allow it to be a great low light lens, it often struggles a bit in low light, keeping up.
Wide open, it is neck and neck with my DA *55 for sharpest lens. Has beautiful out of focus rendering. Can't argue with it in portrait sessions, it just wouldn't work as a walk around lens.