I've had a Micro-Nikkor-P.C 55mm 1:3.5 for over a year now, but never used it since it wasn't Ai converted.
Yesterday I gave in, got a small file, and went to work. I must say I'm impressed that it still looks neat. Had I used a Dremel I'm sure it would have been a mess.
Well, it works perfectly, optically symmetrical across the frame and sharp. I don't always have such luck with old pre-ai or ai lenses. Namely my Nikkor 20mm f/3.5, Ai 135mm f/3.5, Nikkor S.C 50mm f/1.4 etc.
I have a very good copy of a AF-D Nikkor 50mm f/1.8, and this Micro Nikkor is pretty much on par with it pretty much from f/5.6 to f/11. I would rank it as very good, but not excellent. However, focusing closer, this changes. Even wide open, the Micro-Nikkor has some impressive sharpness.