Summary:
The series has some incredibly fun moments and some infuriatingly bad ones, with the fun being much more common. The problem with it and the reason I wouldn't recommend it to anyone is that the author's prejudices are so ever-present that it takes away a lot of the fun and just left me with the impression that the series is both of middling quality and incredibly frustrating.

Grade:
5/10

Review:
It's very hard to evaluate this series. After reading 11 volumes, I can say there were many moments where I was laughing out loud. But there were also those where I was dreading so much the next paragraphs that I skipped them. The fun moments are more common than the bad ones, but the bad ones can be so bad that they erase a lot of the goodwill built before. And the inconsistency of the work can be directly linked to its most distinguishing characteristic.

The series has three genres - mystery, slice of life, and action. The slice of life part is exceedingly fun, specially because of how it fights against some stereotypes. The mystery part is fun enough, bringing interesting plot twists frequently and putting on your toes, though they don't always seem to be all that well thought-out. The supernatural battle par is quite generic, and not that interesting.

The comedy parts of it really made me laugh a LOT. The mystery parts were mildly interesting, while the supernatural battles ranged from mildly interesting to boring.

The really tough part is how enamoured the author is with writing seemingly everything that comes to his mind. Not only are there some troublesome characters and developments (which range from constant paedophilia and sexist jokes that can be ignored to incredibly convoluted rationalizations for those actions that leave a very bad taste), but the author's meta jokes about his own shortcomings and straight-up cheap fan service get really frustrating and tiring.

The good:
The jokes are good, the referential humor is fun, and the meta-comedy is on point.

The bad:
Not only some parts of the books are bad, but they are aggressively so. And the author even jokes about how he's consistently cutting corners. It gets so bad that I skipped generous parts of the worst books and even rolled my eyes when it came time to go back to the uninteresting characters and subplots.

The ugly:
I think it would have been easier to stomach the bad parts of the series if the author did not have his head so far up his ass that he buys all of his bullshit. And that shows in the parts I hate the most: the ever-present subtle sexism of the work (sometimes, far from subtle) and the consistent jokes about paedophilia. I don't really get the fetish about paedophilia in Japanese mainstream media, but there are books and shows where you can just pretend it isn't happening and it doesn't affect the story. Sadly, this series is not one of those. The author is so engrossed by "lolicon humor" that he writes volumes based on a 10-year-old as a "heroine" and there are actual scenes expanding upon the origins of the term "lolicon", so much so that it left me with an incredible uncomfortable feeling while reading some of the books.