I just acquired one of these and have been checking it out. Weather is awful so I've mostly been testing it indoors. On my A77 at 200mm it needs a focus adjust of around -8. That seems to be about right for 80mm too. It seems pretty sharp at f2.8 and impressively doesn't seem to get any sharper as I stop down. There may be a slight loss of contrast at f2.8 compared to f4. That may be due to the third party lens hood, the usual Matin reversible. That may not be as long as it could be, and like many plastic lens hoods it's not very black. I'll try improving it with some sticky back black velour.
I note that the AF locks in at slightly different places depending on whether it came from infinity or close. A lot of lenses do that, but in this case the difference is enough to put it out of sharpest focus. A second half press of the shutter usually sorts it. Is this due to the back lash in the AF gearing? Or is it just the way the AF works? If due to the backlash, is that something that a lens mechanic could tighten up?
I like the internal zoom, not getting longer as you zoom out. That makes it possible to balance the camera & lens perfectly on a tripod with a sliding quick release plate, without suffering annoying droop at other focal lengths as you tighten up the head for a longer exposure. The A77's electronic first curtain removes the shutter impact vibration which softens some long lens tripod shots at lower shutter speeds.
A shot I've been wanting to get for years is a heron in flight along the Water of Leith in Edinburgh. I've got a few out of focus noisy shots of bits of a flying heron. This lovely old Minolta with much faster AF and two more stops of aperture should give me a better chance, not to mention improving my arm strength:-)