Really, there's not much more to say about it. It's just solidly excellent. It features a drug addicted guy who wanders the streets dressed as a nun quoting random tidbits of Revelations and selling tickets to heaven. And it's not like one of those books that puts in something like that just to be quirky and cool - even the most bizarre elements of the text seem totally organic and absolutely believable.
Oh, it's a grand book.