sorry, upon re-reading I see that I probably implied in my second sentence that pocket aces had a good chance of beating pocket aces. I realise that it doesn’t, not at all.
The 87s is better because there are more cards available for straight draws than with a JTs (one of the straights available with JT is AKQJT and two of the Aces are in the other hand).
8,7 7,6 and 6,5 suited (where the suit id different than either of the aces) will all beat A, A the same percentage of the time. However, you are better off having 5,6 because you will tie more often, giving you a higher expected value.
All of the following boards make both 8,7 and 6,5 tie with A,A (as long as there’s no flush), but the boards marked with a * are more likely to fall if you have 6,5 than if you have 8,7:
AKQJT
QJT98 *
JT987 *
T9876 *
98765
87654
76543 and 65432 also give 6,5 a tie, but they give 8,7 a win. Also, if all 5 cards are the same suit as the hole cards, boards like AQJ95 make 8,7 win, whereas corresponding boards like AQJ97 make 56 tie.
So technically, 8,7 suited (where the suit is different than either of the aces) will beat A,A more than any other hand, but you are stll better off having 6,5 because of the better expected value, meaning you won’t win as much as with 8,7, but you will win and tie more than 8,7, meaning you will lose less often with 6,5.