[MINOR SPOILERS]
I give this manga a rating of 6.5. I read it in about a week, give or take a couple of days. I'll make this short and sweet: While it does have a really intriguing premise and fun, fleshed-out characters with a little depth, don't expect anything other than a mediocre ending. This is a very safe, by-the-books manga. There will come a point in the story where you will say to yourself "Oh, so that's probably how it's going to end" and you will more than likely be correct. Very predictable. That's not to say that everything isn't tied up nicely. It's neatly wrapped up and the author even puts a little ribbon on top, metaphorically speaking. Very light-hearted so if you were looking for something with grit, other than the art style and all of the killing, don't expect much grit other than that.

All in all, it was an enjoyable experience. For the most part, that is. You know what they say, it's about the journey not the destination.