I took my 13 year old son to see this on Friday. I was excited to get to experience a Lord of the Rings movie in the theater with him, since he was too young when the first three movies came out.
We both left the movie with the same opinion. We loved it from start to finish. Great action sequences, some comedy thrown in, beautiful scenery, and I thought the characters were all cast well.
At the end of the movie my son looked at me and said, "Is that it"? The three hours went by extremely fast and kept our attention the whole time. A good sign for this movie is that my son sat through the entire thing without having to get up and use the bathroom, which is a miracle in of itself so to speak.
I can't wait for sequel next year!