Summary: I can't write about the optics yet, as I just received this lens. However, I get the idea of caveat emptor when you buy used, but the casing is so worn it's difficult to see the numbers. Not only is there no lens hood included as promised, there isn't even a cap for the lens mount. Working the zoom sounds like a lifetime of sand inside. Not happy so far.
Summary: This lens has surpassed my expectations. It is a very good light lens. The lens does not hunt to autofocus. It is fast enough on the telephoto end (f4 at 70 mm) that I use this lens as my general walkaround lens. This lens is good enough to use for professional work when you do not want to use the heavy pro zoom lens. It was one of the best ebay purchases of the past ten years for me.