I'm currently reading Attack on Titan. I actually started watching the anime some years ago but dropped it after a few episodes, I decided to give it a try again after encountering spoilers from the recent chapters which hooked me up. For now it seems worth it, I definitely like the dark set-up.
I saw many people complain about the art style but I like it better than in the anime, it seems more authentic and rawer, it suits the story more.
EDIT : Isayama is a freaking genius. This manga was a slap in the face, it left me speechless days after I caught up with the most recent chapter. It hurtsso much but thi is so good.That is what I call storytelling.
Honestly, if he doesn't screw up the end, which I don't think he will, it may very well overcome FMA as my all-time favorite.