I really don't know how to rate this one, as it's kind of not a film? Well, not in the traditional sense.
I mean most third parts of a trilogy, while finishing off the main storylines, also had their own sub-arcs to make the film work on its own. Denethor's story in Return of the King, or the destruction of the Second Death Star in Return of the Jedi. This film... kinda doesn't have that. Like it has events that have starts, middles and ends, but nothing that really works on it's own. This is, essentially, "The Desolation of Smaug, part 2".
And that shows from the very start, as the film doesn't really have a beginning, it just picks up directly from where DoS finished, to the point that it was pretty obvious that this isn't actually where a film should start. And a side effect of this is that Smaug, undoubtedly the best part of the second film, is essentially a cameo in this film, with him dying within the first 10 or 15 minutes. Which is a bit unsatisfying, really, because he was so good in the last film.
And, of course, there's the fact that the majority of this film consists of stuff that wasn't in the book. But it didn't annoy me as much as it did in DoS, I think primarily because instead of jumping between "things not in the book" and "things not in the book", like DoS did, it's just one big chunk of "not in the book" all together in one chunk, which made it easier to get through.
And some of the battle stuff (there is a lot of battle stuff) is actually pretty good. Like, really good large middle Earth crazy Peter Jackson stuff that would've been good as a finale to a two-film story. Some of it... isn't as good. I don't think any of it is outright bad (well, maybe one or two bits), but I really don't care about Bard's family (THEY KEEP SAYING 'DA' AND IT'S REALLY ANNOYING) so I don't really care if Bard has to save them from trolls.
Man there were a lot of trolls in this film.
I'd say the worst parts about the actual battle were the fact that Legolas spends most of his time with Orcrist, insread of Thorin, and that Beorn has LITERALLY TEN SECONDS SCREENTIME. Seriously that's fucking bullshit. Take out all of the stupid stupid Kili/Tauriel stuff (which is still BY FAR the worst part of all three films) and give me more Beorn.
But yeah... it's kind of hard to know what to make of it. I... didn't hate it? I wasn't really blown away with it... it just didn't feel like a film. Well, it felt like the third act of a film stretched into it's own things. Which is what it was.
It was cool seeing Christopher Lee fight ghosts, though.