Some of my favorite comedy mangas are 4-koma, and Gugure! Kokkuri-san fits well among them. The description doesn't do the manga justice, but as is typical for these kinds of stories, it's about a cast of wonderfully weird characters and their hijinks. Ichimatsu, the girl, considers herself a doll, and her notion that she is "unfazed by X" never gets old, as does her addiction to cup noodles. The spirits that possess her are similarly bizarre, and amusingly, in terms of comedy roles, the fox spirit (rather than the girl) is the straight man of the bunch.
The series starts great (except for the weirdness of the first 3 chapters being very similar for publishing reasons), and at its best, it compares favorably to the all-time greats. The character humor can be phenomenal and sometimes phenomenally gruesome; some of the meta humor is pretty ingenious; and so on.
The series is almost entirely episodic, however, and past some point (chapter 40? 50?) it gets a bit repetitive. Early on, the series even had a few rather serious moments, but these almost entirely disappear later on, in favor of more randomness. And while the spirits are initially drawn in mostly their human forms, the mangaka switched almost entirely to their animal forms later on - probably because they're easier to draw, but not entirely to the story's benefit. The ending is also a bit abrupt, begins in the penultimate chapter without any prior warning, and isn't 100% satisfying; and the few recurring side characters don't get any closure (like the shy girl trying to become Ichimatsu's friend via dubious means).
Ultimately, I highly recommend this series for the first few dozen chapters, but it's a solid read throughout.