To appreciate this movie, you must understand that there is a stark difference between the writing of The Hobbit and the writing of The Lord of the Rings trilogy. The former is light, while the latter is dark.
It's an excellent movie. It's been more than ten years since I've read the book, but I knew when they were quoting directly or making chapter-name references. There were some things that didn't happen in the book that happened in the movie, but they were done for reasons. Anyway, see the movie when you're able. It's well worth it!