For a debut, this novel is stunning. Palahniuk's narrative voice is confident and funny. The story starts strong but loses steam about 2/3 of the way through, mainly because the big "a-ha!" moment comes way too early and in a very predictable way. If the sheer amount of times the narrator says "I know this because Tyler knows this" isn't a spoiler, then I don't know what is. He bashes you over the head with that declaration dozens of times. But that narrative voice... WOW!
I preferred the movie (I hate to say that, book lovers). I felt the screenwriter, director, actors, and crew took Palahniuk's fantastic ideas and expanded upon them, creating a tighter story and a better ending. From what I've read, Palahniuk agreed at the time too.