I am new to comics, I have collected baseball and basketball cards for years. When a card is slabbed, it can get a grade of PSA 8.0, but the "eye appeal" of different PSA 8.0 cards get a different price. An example would be a 1986 Fleer Jordan PSA 8. If the card is centered, it can sell for up to $1000 more than a non-centered 1986 Jordan PSA 8.0. Corners and Surfaces are also considered Sub-grades, but centering is key when it comes to cards.
What are the sub-grades of comics within the same grade? If I see two different Amazing Fantasy 15 CGC 5.0s, what makes one worth more than another? I have seen comics with the CVA exceptional sticker go for much more than comics in the same CGC grade. What other aspects such as centering, spine, and other factors create more value in a comic that is slabbed with the same 5.0 grade? How do you compare comics "eye appeal?"