I believe my puzzlement and slight disappointment with "The Fire Gospel" is because I was expecting another "Crimson Petal." That's clearly not fair to the author, and I should know better.
This book was fairly funny and was a very quick read. I'd say it was about 175 pages if they'd printed it in a more standard format. But I'm not usually looking for fast in a book. I'd rather have character development, and that's where Faber really let me down. I know almost nothing about his main character and the secondary characters are just there to have the protagonist have someone to talk to.
Nonetheless, the book was funny, particularly if you like reading about a man unintentionally destroying most of what Christians believe about the actual life of Christ. I'd think there isn't a huge market for that, but if that's your interest this is the perfect book for you.