Most other 2nd generation 2.8/35mm lenses from the well known SLR manufacturers are very good. This includes the Canon nFD 2.8/35mm, the Konica AR 2.8/35mm "compact", the [5/5] version of the Minolta MC-X as well as all MD 2.8/35mm, the Nikkor Ai/AiS 2.8/35mm, but also the Yashica ML 2.8/35mm and of course the Zeiss Distagon CY 2.8/35mm. The Mamiya Sekor E/EF 2.8/35mm is no outlier, and while it may be slightly inferior to e. g. the Minolta MD 2.8/35mm, it certainly is as good as the Konica or the Yashica siblings (tested side-by-side on 24 MP FF).

MAMIYA SEKOR E/EF 35mm 1:2.8                  (6 lenses / 6 elements)