It's definitely in my Top 3, but personally speaking, Winter Soldier overtakes it a bit due to it being a more "comic book"-y film. Seeing "TV Zola", the Triskellion and the like gave me goosebumps.
Oh, and here's something else on Letoker:
Brutal assessment of Leto's Joker from "The New Republic"
"But my, oh my, Jared Leto. His Joker is a nightmare—in a bad way. His lame poses and frantic giggling are meant to convey madness, but they more accurately convey the nervousness of a man who realizes his performance isn’t working, and there’s no one there to stop or help him. This is precisely what happened to Jesse Eisenberg in Batman v. Superman, but Eisenberg had the advantage of not having to pivot off one of the greatest villain performances of all-time. After Heath Ledger’s leap into the void as The Joker in The Dark Knight, Leto’s Joker, like everything else in this movie, seems poorly thought through, empty schtick meant to impersonate an actual character. It’s a deeply embarrassing performance, but if you’re playing The Joker after Ledger, you’re sort of asking for it. But that’s the problem with Suicide Squad: Everyone started making a movie before they really knew what they were doing. You need adults in charge, and there are no adults in charge here. The result is, yet again, a total ****show"