I'm a librarian who loves anime, manga, and reading a wide variety of genres.
The resolution to the murder mysteries is convoluted, and I can't help but think that(show spoiler)
I love that Toboso shoehorned yet another mystery-related reference into the story, in the form of Vicar Jeremy, who was basically Jeremy Brett as Sherlock Holmes.
Inside back cover extra: Black Esper.
(Original review posted on A Library Girl's Familiar Diversions.)