Story: The original concept is fairly decent, the fights are also quite entertaining. The world is not very rich though, it feels very plain overall. I also had a hard time getting into it because of some other problem which I describe below.

Art: The artwork is actually fairly good, the main issue is that it is way too repetitive. It's very focused on the characters and lacks background also.

Character: I can't tell who is who, can you? No seriously. This is also why I put so low marks for the art. Poor creativity there. Character progression is also almost non-existent.

Enjoyment: It's very hard to enjoy reading it when on each chapter, I have to figure out who is who and what the hell is going on.

Overall: Repetitive, plain, no humor, straightforward. Not sure what's so good about that manga. The anime is a bit better though, maybe because it doesn't look as plain.