Older R lenses are similar to M lenses of the period, the later designs are outstanding, 28 2.8 100 2.8 280 2.8 and 4.0 180 2.8 90 2.0
People are putting these on digi slr Nikons and are shocked.
I would not buy them for Nikon use, but I know people who have. The Zeiss line is a better value, but 85 is the longest offering.