"Superb."
I am enjoying this book just as much as 30 Rock. It's brilliant and not particularly sappy, and Tina Fey does the reading of the book credit as well (some authors are not such great readers, but this is certainly not the case!).
To those who can't seem to find the PDF mentioned occasionally in the audio book: you can download it from the "library" section right under to the link for the book. It's not essential, but it's nice.