"Sharper" is a subjective term. The red bias in the Nikon increases the apparent contrast, which can make the view look "sharper" than some other bins of similar quality.
Contrast is very important in any activity where you need to separate your "target" from the background, be it birding, hunting, or stargazing. Resolution, OTOH, needs to be compared using an objective "measuring stick" with a booster.
So one bin could out resolve another in a resolution test, yet perceptually look less "sharp" in the field or in a store than the bin with better apparent contrast.
I think this is a major reason why people report differences in which bin they think is "sharper" when they take the "Coke or Pepsi Challenge".
Ideally, you'd like to have a bin that has both excellent apparent contrast and excellent objective resolution, because once you've found your target, you want to see the most detail your eyes are capable of resolving.
However, even though these two factors can be separated out in tests, it's the totality of the view - the contrast, the resolution, the color balance, color saturation, CA control, distortion level, edge sharpness, etc. - that causes a buyer to chose one bin over the other optically. Then how they fit the hand, the face, and the wallet.
Given the small differences in alpha bins' resolution numbers, I'd prefer the bin with the better apparent contrast even if it's a hair's breath behind the other in resolution, because most of my birding is done in fairly dense woodlands.
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