Yes, the books are better, but that's no reason to knock the Harry Potter film series. The first few movies are enjoyable, preadolescent tales that are fun and family-friendly, but by the time the heroes are actual teenagers, the stories are darker and much more serious. Death, betrayal and the role of fate are all explored. However, what makes these films such powerful teenage dramas are two incredibly relatable themes: You don't have to be related by blood to be family, and good friends can help get you through anything.
None of us has ever been to wizarding school, fought a giant snake or failed a potions test, but many of us have lost people we loved or had to face an extremely difficult task. Having a friend to lean on during those times makes all the difference -- muggle or not.