I would just like to say that 13 straight hours of The Lord of Rings is quite a challenge. Not quite climbing Mt. Everest or running a marathon sort of challenge. But a challenge none-the-less.
The Return of the King was quite good, even if the ending was a bit too shmaltzy. And I personally want to punch every person in the theatre who felt the need to cheer every five-fucking-minutes because something minor just happened.
Aragorn entered the scene...time to cheer.
Someone mounted a horse...time to cheer.
An orc was killed...time to cheer.
The New Line Cinema logo was displayed....time to cheer.
And so on, and so on. Certainly you can see how that would get irritating after the first half-hour of the movie.
But I'm sure others will have more in-depth and useful reviews of the movies. As I'm not a fanboy, I feel no need to pick apart every little discrepency compared to the books. I will, however, leave you with this: go see it, it's good.