I am so happy that they are taking the time to tell this story, by making it into two parts....Although, it is my opinion that most HP fans would HAPPILY sit through a five hour movie ;) I am reluctant to suggest an appropriate age for viewing this movie. I would probably agree that the PG-13 is pretty accurate. My children enjoy the books and movies, but this story is very dark and sad. The visual violence has gone up a notch. I absolutely LOVED the movie and would go to see it, again, today.
I really enjoyed Eclipse. I think it is the best of the Twilight Saga, so far. There was enough action to keep (reluctant-to-attend) male audience interested, as well. I do not think this movie is appropriate for children under 13, as a general rule of thumb. My younger children have seen the other two, but this one has more romance and graphic violence.