One word: disappointment.

Rating: 7/10 (11 January 2015)

The feeling of disappointment that resent me when I left the theater was due mostly to seven things. First, seeing Smaug being killed like 5min later after the start of the movie was a hell of an anti-climax. It would be better if that same scene belonged to the second episode of this trilogy - that'd be a good way to separate content.
In second place, Bard, the character that kills Smaug, plays a persona that has no ending. You see it the last time like 45min before the ending of the movie and it'll remain untouched. From that parallelism of the argument, (3) the character of Alfrid is really forced in the storyline. It doesn't add anything to the story and this kind of trick is usually played by blockbusters to fill space in the screen.
Forth, even though I'm a really huge fan of Lee Pace, his character, Thandruil, is weak to average. I guess that since the beginning we was not the wisest choice to play this character. But even worse than this is (5) Evangelline Lilly that has the worst role in the entire trilogy as Tauriel (I don't know how she got the role, really). The face she puts to Thandriel when Kili dies in front of her is just amateurish. I'd even say that that same face is the most fictitious thing in the entire movie.
Sixth, the production of this movie was the weakest of them all. I even got out of the theater thinking if the team went to New Zealand to shoot anything - everywhere you looked, you'd see cheap CGI. There was no preoccupation at all in turning things more realistic. This CGI is at the level of the one used 10 years ago for the original trilogy. Only back then was the awesomest thing. Today it's just cutting on spending. Just a commentary: even HBO gives more importance to quality CGI than a movie with a budget around a hundred of million dollars.
To end, the connection to the original trilogy is also very amateurish and quick. It seems that they gave no thought to it at all.
Concluding, this episode was really disappointing regarding the expectations that were created. This is actually the worst movie I've seen from Peter Jackson, it's the worst of the entire Lord Of The Rings movies but it still is a medium-good movie looking the titles of last year. Yet, for Lord Of The Rings movie, it's just sad.