The Force Unleashed will not be a lasting experience. It's fun, but you can't help but feel a tingle of disappointment when thinking of what it could, and should, have been. It also may be a somewhat frustrating experience at times. But if you like Star Wars, you will put up with it.
Why you ask? Because of the story. A game with a great story is a rare and beautiful thing but a great Star Wars story? Now that is a truly epic achievement.