After two days of use, I don't see anything exciting with this lens. It's one of those Cimko OEM lenses that has many names on, like Porst, Revue, Chinon, and others. Pretty well built with smooth focusing, but nowhere near what the Takumars feel like. Acceptably sharp when stopped down, but a bit soft wide open. The bokeh actually good. I know two days of use doesn't do justice to write something about a lens, but I have used its cousin, the Revue 55mm f1.7 for some time. They are basically the same lens.
Below are a few pictures taken with it. Click on the picture to see a larger version.
Flower -- Panasonic G1 with K-mount Topcor 55mm f1.7
Rail Road -- G1 with Topcor 55mm f1.7
After Sunset -- G1 with Topcor 55mm f1.7
Waiting for light to change at Lakeshore & Logan -- G1 & Topcor 55mm f1.7