I went and saw The Hobbit: The Battle of Five Armies yesterday, and have been thinking since of what I might say about it. I don't really have anything extensive to say, but here are some assorted thoughts.
(1) It is massively better than the second movie. They wrapped up the fan fiction material (Bard's family, Tauriel the Largely Useless Romantic Interest, Alfred the Snivelly, and Azog the Defiler -- there really is a remarkable amount of it) somewhat better than I expected. Martin Freeman crying over Thorin, and the dwarves paying their final respects, would in itself cover many sins, and I heard people sniffling all over the theater at that point. As with the previous ones, the acting is actually fairly good, even with the badly written made-up parts.
(2) There are two ways in which they certainly should have gone with the books. (Always important to remember that, despite the name, these movies are not The Hobbit but prequels to the Lord of the Rings movies.) First, Fili and Kili. The book is very, very clear: Fili and Kili do not survive because they die defending Thorin Oakenshield "with shield and body". Fili's death is entirely wasted here, and while they do OK with Kili's death, in no way is it better than the death he has in the book.
Second, the assault on Dol Guldur, while mildly interesting, is very low-key when it should have been rather impressive. Why in the world the White Council would assault the Necromancer on their own when two of them have direct command of formidable Elven troops with literally millenia of experience in fighting dark forces is beyond me. And what is more, the books, brief as they are about it, are clear enough that Saruman used siege engines against the Necromancer, and that his war machinery was a major factor in the White Council's success. It was not only disappointing in itself that this was dropped, but it was a missed opportunity: As a prequel to the Lord of the Rings movies, what really needed to be shown was how terrible a military foe Saruman can be.
(3) There are some points where they probably should have gone with the book, but did OK with their different direction. The death of Kili was one -- it worked out fine as they did it, but there was really no particular reason to do it the way they did it. The dragon-sickness issue ended working well; it was a bit overplayed, but they were at least smart enough to realize that, if they were going to put this sort of emphasis on it, they should at least point out explicitly that Bilbo is resistant to this sort of domination of mind. The changes made in Thorin's death did not make it better, but due to some excellent acting and reasonable balance, they did not make it worse, which would have ruined the trilogy in and of itself. I wasn't hugely impressed with how they handled one of the most memorable lines of the book -- "The Eagles are coming!" -- but at least it wasn't badly botched. Bard doesn't strike me as very like his book counterpart, but he actually ends up being a very good character.
There was one change they made that was very, very good -- the acorn, which made the point that needed to be made, clearly, quietly, simply, and did so effectively enough that the theme of home was emphasized despite all of the many things going on.
(4) Rather curiously, most of the outright mistakes were special effects failures. Who in their right mind would ever have thought that the negative was a good effect for Galadriel? It was stupid in the LOTR movies and it was just as awful here. Some of the special effects for Thorin's mental state could have been done without. The earth-eaters were, I think, a less impressive effect than they were hoping.
Pacing has been a problem throughout; the pacing is much better here, but it seems clear that some of the things at the beginning of the movie should have been in the previous movie.
One of the other outright mistakes was the Elves leaping over the Dwarves in battle, which is such an extraordinarily, jaw-droppingly stupid tactical move that it would have made more sense if it were done with Radagast's rabbits than with Elves who have been fighting orcs for centuries. And it was right after one of the really great moves. Jackson does not actually handle battle scenes very well -- one recalls the often awful handling of the battle in front of Minas Tirith -- but the Dwarves phalanxing and forming a shield wall was genuinely good and awesome. The moment was ripe for the Elves to flank the orcs, crushing them between the two armies. Instead the Elves decided to crush themselves between the Dwarves and the Orcs and force the Dwarves to break their tactically excellent line, all in order to have a fake-awesome moment.
This has, indeed, been a running problem with Peter Jackson: the inability to tell the difference between awesome and fake-awesome.
(5) Some things I liked: the acting, as I mentioned, was good all around. I liked the acorn scene. I liked how much of the stuff to do with Laketown, and its uncertain future after Smaug's attack, was handled. As with the other movies, sometimes the little details are excellent. And it did fairly well overall as the final act in the prequel series to Jackson's LOTR movies. Some of the jokes were reasonably good in this one.
(6) There are two ways in which this movie can be evaluated: relative to the books and solely qua movie. Is this a great adaptation of the book? No, although, again, this is the best and least flabby of the three, and massively better than the second. That's unfortunate, in many ways. There was so much potential that was squandered, and there's really very little chance of another serious attempt for a good thirty years. There have in the three movies been three episodes, however, that were very much worth seeing on the screen: Bilbo and Gollum in the riddle game in the first one, the unfortunately brief bit of Bilbo rescuing the Dwarves from the dungeons of the Elf-King (at least when they are actually still in the dungeons), and Bilbo at the death of Thorin here. All of them are reasonably well done.
I think it fares much better if we ask, "If we forget that this movie is adapting Tolkien, sometimes well but often badly, and just consider whether it stands up as a movie, how well does it do?" I think this third offering stands up fairly well by such a standard; it actually ends up being more coherent than a lot of movies these days, and it has a better message and deeper feel than most big-effects movies ever do. The acting saves an immense amount. Martin Freeman, again, is excellent. Richard Armitage did brilliantly with a somewhat oddly written character path. It does most of the movie-prequel things quite well. I was worried about the score in the beginning, but overall it turned out quite well. And one thing that may not come out in any of what I've said above is that the emotional balance of the movie is for the most part quite good -- we get genuinely funny, genuinely sad, genuinely heartfelt, genuinely silly, and so forth in about the right proportions for a movie this length, so that it actually does well on one common standard against which movies are measured: unlike the previous film, it did not drag, and it stayed interesting.