This was quite possibly the most visually stunning film I've ever seen. Amazingly, despite the dreamscape-like transitions, it was never disorienting, which is a tribute to McKean's directing talent. The plot was typical Gaiman fable material, as opposed to his more intricately-woven novel-length plots. Given that limitation, I would have to say this is not a "great" film; but it is totally enjoyable, entertaining, enthralling, and I would even go so far as to say ground-breaking. I plan several re-viewings.
I used to be a snob when it came to comic books: that was before I was introduced to Neil Gaiman's work. My gentle introduction was Exiles, from volume 10 of his Sandman series. It appealed to the visual and orientophilic streaks in my nature, sealed with a feline lick. His darkly comic novel Neverwhere cemented his status as one of my favorite writers. Indeed, that book became one of my all-time favorites: I remember my first reading of it as an experience to be savored. The hero was a disarmingly ordinary everyman, the villains were chillingly evil, and the supporting characters were lovably eccentric.
Dave McKean entered my conciousness simultaneously with Gaiman. It slowly dawned on me that here was an artistic genius of stunning inventiveness. To label him a mere illustrator is a grave disservice: while an adequate comparison in the visual field escapes me, I am put in mind of the writer William S. Burroughs, whose prickly new style of composition in words precipitated a furor that still reverberates after nearly fifty years.