My first thought after a page or two of this book: "Hey, this guy writes just like Vonnegut. Bad ass!"
This book is hilarious, smart, absurd. Me reading the book: "Ha ha ha. Stop it! Ha ha ha. Oh, shut up!" The hilarity is occasionally suddenly stopped with a passage that is dead serious without making the narrative choppy or seeming to go off track and rant for a while. The story flows despite the momentary step away from humor.
Downsides are it's not really compelling, and there are so many characters. I could have put the book down at any time during the first 1/2 of the book (at least) and thought I had the gist and didn't really care how it ended because for a long time, it didn't seem to be going anywhere.
While the story moves generally forward, it keeps looping back and giving you more information about episodes you already know a little about. For a good chunk of the book, I wasn't so sure it was even moving generally forward. The good part of this is lots of, "Oh! That's what was going on there," and, "Oh! Those two things happened at the same time," and, "Oh! He made it seem funny at first, but that was actually really fucking horrible. Oh, God."
After finally coming to the end of this book, I can say it was worth it. The payoff takes a while, but I assure you - it's there.