I am a fan of the series and was waiting for so long for the movie adaptation but unfortunately I believe they didn't give justice to it.
In my opinion, what sets the book apart from any other mediocre fantasy books is that the main character who is just 12 years old is capable of being so cold hearted and greedy (not to mention sooo intelligent) and to see him slowly become more and more human in the series without losing respect for how incredibly smart he is. All of these were lost in the movies.