First, if you want to see this up front, this movie is VIOLENT. It's realistic, some of it is a little toned-down, but most of it is "true grit" western violence. Some iffy parts would include the scene where a father cuts his son's fingers off and stabs him, hence the bad role models sticker. There's some bad language in many of the scenes as well. Rooster Cogburn is drunk a lot.
However, if you watch the original True Grit with John Wayne, it's gritty with violence as well, and includes the finger cut-off scene. So the Coen Brothers didn't over-do that.
My MPAA rating:
PG-13 for realistic violence throughout, language, and alcohol and tobacco use