Very good.
This is hands down one of the best ongoing mangas in the world right now.
The art is top notch.
The stakes are high and people die, and our protagonists are in very very dangerous situations.
The fights are cool.
Interesting characters, character interactions and beautiful character designs.
The world is absolutely interesting and unique(it takes place in an entire whole UNIVERSE).
And its in SPACE!
Also, Its getting two games and an anime very soon, so it will only get more popular from here on out.
Kudos to hiro mashima for giving us a master piece of a manga.