I assembled a Turkey Red set a couple of years ago. Bought cards any way I could, graded or raw, and completed the set just as SGC started to grade T3s so almost all my slabbed cards are PSA. It seemed to that they were all over the map with their grading and that they don't have consistent standards when it comes to TR's. I got the impression that corner wear and creasing trump other criteria like surface condition. I have twos that are nicer than fives (and heaven help you if you have a microscopic pinhole on an otherwise flawless card). Submitted for your consideration is this PSA 5 of Red Kleinow. Corners are OK but bumped and frayed, no creases (scratch on slab at llc) but the eye-appeal is compromised by myriad foxing marks and a tad of paper loss (@ 44 Trying to Catch...).
Compare it to McIntyre, a relatively unscathed four.
Or even Mullin, a two primarily on account of a 3/32" tear at lhs. Back clean as a whistle.
For all I know these may all be technically correct grades; I am not like some of you who can grade a card at fifty paces. It doesn't even really bother me except when a card's grade is touted as being correlated to a certain price. A set of decent scans beats a grade any day when it comes to buying cards, especially Turkey Reds.