Step Brothers is totally what you would expect - especially if you are expecting a bunch of cheap laughs, grade school humor, gratuitous swearing, and some classic Will Ferrell. I laughed out loud many times during this movie. The only mistake I made was seeing it by myself. I definitely think it would have been funnier if I would have had someone to laugh with me.
Side note: Someone in the audience was actually dumb enough to leave their phone on. To add to that, he ANSWERED his phone and talked loudly for a minute explaining that he was in a movie and he would call back later. "Maybe we can meet for dinner, yeah, sounds good. Oh, yeah it's funny....." SERIOUSLY?