The story line is great, it is the main reason you should watch it.If you like an anime that makes you THINK, then you must watch this, I ended up watching 1 episode due to being recomended to watch it by a college friend, I literally sat and watched all episodes in one sitting, I was totally hooked from the first episode.
Now about characterisation..
The characters all rock, have their own personalities which makes you love em and hate 'em simultaneously, You end up rooting for both sides, the good and "bad" because of it, it's very entertaining to watch.
The animation is awesome, and the story is just insanely good, can't get enough of it really! I read all the books and watched the movies too after seeing all episodes, my fave anime..
It is worth watching and everyone should watch it..
