I don't understand people who thought the movie was long. It was the perfect length. And it was the shortest Jackson-Tolkien film yet! Without the credits it's just a little over two and a half hours. I would say it is the fastest paced and most action packed of the four films so far. None of that Lothlorien crap that brought Fellowship to a screeching halt. There is one Rivendel scene but it's short and awesome--and involves two of the funnest cameos in the entire film (actually three, but one especially is a treat to see). Won't spoil it, but yeah.
Long and boring? Hate to see what those reviews thought of the other three films.