I've got one of those lenses and the way you describe the mechanical aspects stacks up with mine 100%. When you compare the action of the focussing ring, aperture ring and blades with those of Takumars, you're comparing what IMHO sets the standard to something that isn't remotely in the same league. The Zeiss is (I'm open to correction here) of GDR origin (and we all know that countries with 'Democratic' in their name invariably aren't!) and the quality of most Eastern bloc goods of that era was at best inconsistent and at worst awful. That said, the mechanics of my Flektogon are so abysmal that I've never tried it. It would need a full CLA to be of any use. They do have their followers and even if the optical quality doesn't match what you'd expect of a Takumar, the character may have its own appeal. Whether it's worth spending money on, I don't know, but personally I'd put the money towards a Takumar.