By reputation it is inferior, being noticeably soft in the corners. At the time it was the least expensive option and those paying more were probably expecting a better lens and probably got one. Time may have been kind to some examples though which may now outperform other names like the Skopar of similar vintage that have suffered more. That is the problem now, what was a good lens from new may now have deteriorated and vice versa so individual comparisons from others are largely irrelevant it is the lens you have at hand that matters. Note how there is still, see "lens rentals" reviews, very considerable sample variation in modern, very expensive lenses, how much more in the earlier hand built glass? Unless the reporter has experience of several samples opinions can be taken with a pinch of salt, even this one.