I listened to the audiobook version, read by Franken. It managed to make what could have been a very dry account of ways the conservative media spins the facts to make their points into an entertaining, amusing, and educational experience.
(And yeah, it's not just the conservative media - it's natural for every side to cherry-pick facts that support their positions. But as a liberal, I enjoyed this, and parts of it got me even more fired up about the issues.)
I'd contrast this to e.g. Colbert/Stewart by noting that in this book, the humor always supports and underlines the political point, while their humor tends to be the main point, supported by the political material.
The only chapter I truly disliked was the one where Franken attempted to infiltrate Bob Jones University. I squirmed throughout.