This is one of the more imaginative stories, with an interesting world and a lot of potential. Feels like a 9/10, but it's not.
The characters are inconsistently written, but those inconsistencies are consistent (in a range) so it's bearable. The situations are undercut quite often and it feels like the author is trying too hard to subvert expectations, as it happens often and sometimes works really well and sometimes leaves you feeling annoyed or burned.
The characters, themselves, rely too much on their one major personality trait to the point I wish they would develop, which they never seem to do.
The mystery is good, however, and the comedy is somewhere between Gintama and Bleach. The world in interesting and it feels like this could have been a couple hundred chapters long with the right plot treatment.
I'd gladly read more of this than most of what's out there, and there is definitely something special that the longer lasting stories have, minus the character development... which may have been why this got the axe.
It's not perfect, but it is great.
(P.S. I've watched Sanctuary, and while I do see the connection on the surface, the actual character comparisons are only somewhat accurate in their plot roles—leader/researcher, new guy, etc.—in reality, the characters are nothing alike and I, personally, think Sanctuary and this manga take similar concepts and run them in very different directions.)