I tore through the entire book in a day, but despite that I don't want to give it a full five-stars. I'm a fan of comedic footnotes [see Terry Pratchett:], but the self-promotional footnotes started wearing a little thin about halfway through the book. And for some reason Izzy irritated me a bit more than usual. I went through a similar thing with Janet Evanovich. I read through the first six or seven books in the Stephanie Plum series in no time, but just found myself getting more and more tired of the main character's behavior.
I know Izzy is supposed to be zany and kooky and I'm sure the books would not be as much fun if she only made sensible, adult decisions, but I think Lutz pushes it a bit too far sometimes.
Regardless, it was a fun little read and I'll definitely pick up the next in the series when that comes around.