Of the three Al Franken books I've read, this one is my least favorite. It's also one of his earlier books, before Lies and The Truth, so maybe he just hadn't hit his stride yet, politcal satire-wise.
Rush Limbaugh is a Big Fat Idiot and Other Observations has a great title, mostly because it's to TRUE. How it differs from his other books that I've read is that it is a series of independent essays compiled into a collection. And while I enjoy his sharp wit and scathing humor most of the time, some of the stuff in this book seemed a little mean-spirited, even for Franken.
He spends an inordinate amount of time on Limbaugh's weight, which doesn't seem fair. Of course, I could just be a little sensitive in this department myself. But where Franken really shines is in his analysis of all the crap that Limbaugh says. This is where Franken's talent truly lies: in exposing Limbaugh (and others) for the outright liars and dangers to society and free thought they are.
The book doesn't focus strictly on Rush Limbaugh, though time and again throughout, Franken comes back to him. It also talks about some of his experiences participating in various political rallies and campaigns, which are fun to read. Franken really knows how to make an impression, I can assure you.
There was one bit that made me snort. There's an essay titled, "Stop This Man Before He Kills Again," in which Franken address the absurd claims that the Clintons are murderers. Franken was at the White House Correspondents' Dinner and shook hands with President Clinton. He says, tongue firmly planted in his cheek, "Had I known at the time that the man was a murderer, I would never have shaken his hand. I have never knowingly shaken the hand of a killer. Once I did a fund-raiser for Pol Pot, but that was before I'd seen The Killing Fields."
All in all, an okay book and another good example of Franken's sharp wit and ability to use humor to cut through all the crap. I must admit, however, that the book left me a little cold in the end and gave me the feeling of being a little too mean.