Here's the thing... you know where this movie is going to go. All the plot points are pretty obvious; it's never going to get ahead of you, even when the "twists" start in the back half.
But it's pretty fun to watch. DeVito and Bates are completely cartoonish and over-the-top -- and that's what makes them great together. Edward Hermann and Christine Baranski are perfectly cast, though I wish we'd seen more of them. Everybody else is fine (Bob Odenkirk is a bit wasted -- given that "anger management" is a major theme of the movie, casting a man known for his comedic anger in a role where he doesn't get angry is strange), except for Livingston.
Ron Livingston is the center of the movie, and there's a problem. He commits to playing the role a certain way, and you don't understand why, and you don't really like him. More than an hour into the movie, they reveal why he is acting the way he did, and it kind of makes sense, but he's already lost your sympathy by that point.
But if Devito and Bates as total white trash screaming at each other, lines like "If brains was chocolate, you wouldn't even have a M&M" is something you want to see in a comedy, then you should see this movie, because there will probably never be another movie where that happens. If you go with them, they keep the movie entertaining.
Stick around for the end credits, their duet is almost certainly the highlight of the film. It's in the film, but most of the lyrics are obscured by the dialogue; the song plays in all of its glory over the end credits.
