Finally, I've made up my mind and ordered this vintage, renowned lens! It arrived today and I've just "unboxed" it.
All Takumar lenses are famous from their sharpness and great optical quality. This model, with f1.4 apeture is placed among the best. What's interesting, the performance of those lenses is boosted by the radioactive thorium oxide - see the yellowish tint at the front element? It was quite common at that times and the engraved S/N indicates, that my copy was manufactured between 1964-1965. Several tests confirmed the radiation is minor so I guess there's nothing to worry about.
As a bonus to my copy, the previous owner bundled lenses with extension tubes, so I'm going to try macro photography as well.
Can't wait to have a nice session with Takumar mounted at my camera...