Here is an interesting study JB reported (via copy and paste from another forum)......a very accurate assessment IMO.
Yes, human eyes vary considerably, and there are even some general trends. On average women are more sensitive to the blue side of the spectrum, and men more sensitive to the red. The pupils of older people don't normally open as widely in dim light, which means a "full-sized" exit pupil of 7mm or so doesn't make as much difference to them as quality glass and coatings.
But our brains also play tricks on us. Several studies have down that price affects not just our judgment, but can actually make the part of the brain perceiving anything respond favorably. One study I came across was of a wine tasting. A bunch of bottles of wine without any label other than price were tasted by a bunch of people, some "sophisticated" wine drinkers and some not. The people were told they were rating new wines as an aid to wineries.
The price labels were phony. Some $5 wines had $30 labels, and some $40 wines had $8 labels, and so on. Overall, the more "expensive" wines were given higher marks, and it didn't matter if the taster was a wine sophisticate or not. That's not surprising, but the people were also hooked up to sensors that recorded responses in various parts of their brains. When most people responded favorably to a cheap wine, it wasn't just price prejudice. The part of their brain involving "taste pleasure" also lit up.
One of the tests I ran about a dozen years ago was covering the name of two brands of roof-prism binoculars of the same magnification and objective-lens diameter with duct tape. One was a high-dollar Big Three Euro, and one was a Japanese binocular costing half as much--though it was the "affordable" favorite of the year. They also resembled each other physically enough that most people wouldn't know the difference.
I don't recall the exact results, but out of about 20 people slightly more picked the Japanese binocular over the Euro, and a few called it a draw. There weren't any price tags on the binoculars, so I think the results were valid.
But binoculars also vary from year to year. Those same two binoculars would be considered very good today, but not top of the line. Some people keep chasing the flavor of the moment, but one thing I've noticed is that while individual eyes vary in optical preferences, skill in glassing varies even more.
