I own a Vivitar 135mm f2.8 for Minolta SR bajonett.

It is a solid, really good performer. Sharp but not the best concerning bokeh, but only visible bokeh problems when the background is not far away.

If the background is strongly blured the bokeh can be very nice.

Mechanically a really nice lens.

If I don't had a MD Rokkor 2.8 135mm (4 Elements), which is still a little better, I wouldn't mind using the Vivitar all day for my 135mm task.

I would prefer the Vivitar against my Tokina 2.8 135mm for SR which also is a sharp lens.

Nearly no lemons in this range.