I know I am considered a Tolkien purist, but I can accept some things like the presence of Legolas (Orlando Bloom) since he must have been there somewhere. Even, the addition of the female elf, Tauriel, for love interest (Evangeline Lily) I can accept. But I can't accept a love triangle with Kili (Aidan Turner) at the third vertex. And I can't accept the great abomination that is Radagast the Brown (Sylvester McCoy). This is a character, who is mentioned in only one sentence in the book, and has become the Jar Jar Binks of Middle Earth. Luckily, we see Radagast only briefly in the third installment of The Hobbit: The Battle of the Five Armies. Unfortunately, the love triangle is front and center.
The Battle of the Five Armies covers roughly the last third of the book. It begins with the destruction of Lake-town by Smaug, and his death at the hands of Bard. Even this iconic moment is not anything like the book. There is no thrush to tell Bard of Smaug's weakness, and we have to have a conversation between Smaug and Bard before the arrow flies. This is followed by some Appendix B stuff, where the White Council drive Sauron out of Mirkwood. It is definitely nice to see Galadriel (Cate Blanchette), Elrond (Hugo Weaving), and Saruman (Christopher Lee). Galadriel, in particular, rocks the ring of power.
Then, it's back to the Lonely Mountain where everybody and his brother shows up. First, the lake-men looking for their gold, then the elves looking for their gold, then dwarves looking for their gold, then the Orcs, well you get the idea. This part of the movie including Bilbo's theft of the Arkenstone bears some resemblance to the book. Huge amounts of screen time are devoted to another non-character who is the assistant to the Master of Lake-town. He is a Wormtongue ripoff and serves no useful purpose at all to the plot.
It is the actual Battle of the Five Armies which departs completely from the book. First of all, one of the armies is missing. There is only one Warg in evidence. Once Thorin and the other dwarves join the fight, it looks like we just have to wait for the arrival of the Eagles and Beorn but no. The actual description of the battle in the book doesn't take up very many pages, but we do know that even after the Eagles arrive, it still looked bad for the good guys until Beorn arrived and "broke like a clap of thunder" on the Orc army. Then, "Beorn stooped and lifted Thorin, who had fallen pierced with spears, and bore him out of the fray...Fili and Kili had fallen defending him with shield and body, for he was their mother's elder brother." None of this happens in the movie. Beorn appears on screen for about one second. We don't see him again. Instead, Thorin, Fili, and Kili jump onto large mountain goats and ride up a mountain to battle Azog, the leader of the Orcs (and another character mentioned in only one sentence in the book), and a whole orc army singlehandedly. Luckily, Legolas and Tauriel, who had disappeared for most of the movie, show up to help out. But this is also bad because Kili dies defending Tauriel, not Thorin. Thorin is fatally wounded in ridiculous single combat with Azog on an ice floe. He does have his death scene with Bilbo, which is sort of out of the book, but this is superseded by a long more important scene of Tauriel's grief over the death of Kili and Legolas deciding that this isn't the woman for him.
There are a few nice scenes in the movie. Smaug is still great, but he is gone after 15 minutes. We have the classic Peter Jackson moments that we have seen in all the movies where he makes characters do things that they would never do. First, the King of the Elves decides he's going to quit and go home during the battle, and Thorin decides he doesn't want to fight to save Dain and the other dwarves. And, then there is the stuff that is just bizarre. What's wrong with riding horses? Why does Radagast have a rabbit chariot, why is Dain riding a pig, and why is Thorin riding a mountain goat?
The best thing about these movies and about this last installment is still Martin Freeman, who is inspired casting for Bilbo, and also Ian McKellen as Gandalf. Luke Evans is very good as Bard, and the dwarves are good although most of them are off camera throughout most of this movie. When Bilbo is on camera, the movie rights itself briefly and The Hobbit returns, but then it veers off again.
Finally, is it really over? This movie ends with Legolas heading off to look for the Dunedain and a young ranger named Strider. Can they fit in another movie or maybe a trilogy between the end of The Hobbit and the beginning of LOTR? And then there is The Silmarillion. No, please, no.