I saw the movie this weekend, and I have to say that I think a lot of the reviews were unfairly harsh.
Yes, it is "dumb humor," but you know what, I don't always need to be intellectually enlightened every time I go to the movies. Sometimes it's nice just to be entertained.
You are lying to yourself if you can't admit that car chases and watching stuff blow up is fun.
Without giving anything away, let me just say that Johnny Knoxville's previous job experience served him well here.
I also thought that the movie did a great job dealing with the "politically incorrect" aspects...i.e., the big Confederate flag on a car named "General Lee." They couldn't really change any of that, but they had fun with the clash with modern culture.
Bottom line, this film isn't going to win any Oscars. You will not learn a darn thing watching this movie. But it is very very funny, and my job is as depressing as hell lately, so that's enough for me.