Wonderful, but tred with caution
Jarhead is a brilliant film. With exceptional pacing, acting, and cinematography, and a fascinating premise, it does well across the boards. All the same, this is one that I would strongly caution parents about; I would recommend that only older, very mature teens be allowed to see it. There are some disturbing war images, alarming transformations in the soldiers, and a few scenes of graphic sexuality; but what truly is the problem in this movie is the language. When the CSM reviewer there were hundreds of instances of the f-word, this was not an exaggeration: to be exact, are 278 instances of that swear alone.
So: adults, enjoy. But in terms of your teenager(s), think wisely.