Think it has to be Mania. That show had no right being any good considering the build, but the card turned out pretty damn fantastic. Rusev's enterance was GOAT, and it was a solid match (outcome sucked). IC Ladder match was crazy insanity. Best RKO ever. Main event was just a fun as hell match of Brock hurting Roman, and the cash in was perfect.
Summerslam and HIAC were both good. Summerslam's issue with me is despite two really good matches. Seth/Cena and Taker/Brock (which had no business being as good as it was). Two screwy finishes drag it down.
HIAC had two whopper matches in Bray/Roman and Taker/Brock again (once again no business being as good as it was), but the WHC match was trash and its hard to rate a PPV high when your title match is basically a mid card match behind the two cell matches.