Being Neil Gaiman's self-described "best work," there's an expectation that comes with Mr. Punch
that is hard to fulfill. This is even harder when you base your expectation on the fact that no one can really describe it in full without giving the plot away. Simply put, the premise is this: A boy visits his grandfather's arcade and discovers a mysterious puppet show and dark family secrets.
That being said, it's an excellent story. The narrative style feels as if Gaiman himself is telling the story of his own childhood, which, as the story progresses, becomes very clear is most certainly not the case. There's everything that you would expect from a Gaiman story; borderline-horror dark fantasy, mysterious characters, and plenty of violence.
(Possibly the most startling line is "Hooray! Now everyone is free to do what they want!" which out of context
seems like a joyful cheer, but with any knowledge of Punch And Judy, will in fact be stomach-turning.)
Dave McKean's artwork is by far the best part of the graphic novel. Instead of something in the style of Black Orchid
or Arkham Asylum A Serious House On Serious Earth,
McKean's work here is more like the accompanying artwork for The Sandman
— a mixture of photographs, models, and paintings which adds to the mysterious feel of the story.
The story is relatively short compared to Gaiman's other works, and could be read fairly quickly, but there's enough visual material that you could spend a great deal of time looking over it. It's a wholly recommended read, but it's (arguably) not something that you can take much away from or think on.