I have the Nikon 28mm f/2.8 AIS and the pre-AI Nikon 28mm f/3.5. Both are excellent lenses. I prefer the f/2.8 for shooting landscapes and general subjects. I prefer the f/3.5 mounted in reverse position on bellows for shooting close-ups and macros.
I paid more for my f/3.5 than I did for my f/2.8.