I have a 20mm f/4 AI-s. Personally I do not like the feel of the focus ring. It is not well damped and not silky smooth like my other AI-s lenses. It feels like my older non-AI lenses. I have no idea if this is due to its age or mechanical wear and tear, or if it was an inherent characteristic of the lens.
Does the newer 20mm f/3.5 AI-s NIKKOR perform better in this regard? I am not interested in the 20mm f/2.8 NIKKOR AI-s because it does not take 52mm filters.