The Killing Joke undoubtedly has some of the best Batman art around. Panels of the Joker and Batman are unbelievably, creepily detailed and realistic.
That being said, I felt like the story of The Killing Joke let it down. Not because it was a bad story, but because it didn't feel like it got enough space from the mere 47 pages that make up this story. Minus the pages that include an older, forgotten part of the Joker's history, we were left with less time than should maybe have been given over to the rest of the story.
I felt that the story in this was one that is typical of a fight between Batman and his arch-nemesis. The additional themes presented an interesting side to the story, although, as previously mentioned, I didn't feel like they got as much space as they should have.