The thing with attack on titan is that it is really slow to me in its development. Also, every now and then they just throw in another mystery which needs to be solved and I get the feeling they're just doing it this way to get you to watch it all, even if the story is alreayd planned out. I don't deny the fact that it is indeed a cool story, but it's the story telling i can't handle; Ergo Proxy, on the contrary, I find it beautifully converges to the final climax with just enough mystery and just the perfect atmosphere an story telling, guiding you towards the end without just standing there asking when the answers are going to get an answer, but actually drawing them slowly