I began reading this because I tried to watch the anime twice and couldn't get hooked. I know it's very highly rated so I gave the manga a try and found the manga much better suited for telling this type of story. Anyways, on to the review:

Story: The story is really good. I don't rate it higher than 8 because I found there to be too many characters and I had to go back to remember who they were speaking about.

Character: I know a lot of people praise the characters, but I found them to be pretty predictable in terms of personality. Which hey, it's not a bad thing, it made the plot of the story itself even more impressive.

Enjoyment: Honestly the pacing of this story is fantastic. By the end of every chapter, I want to read more. I stayed up way too late just reading on and on for this story.

Overall I liked this. The manga was good. Do I recommend it? Sure. It's got a great plot and keeps you hooked.