Saw the movie yesterday and thoroughly loved it. The writers did a very good job including supplementary material throughout the movie and laying out the groundwork for character motivations and just general reasons for people being where they are (or are not). As well, the tweaks they made to the canon were done well and in my opinion were acceptable.
I am referring to Azog, mostly. According to canon he is beheadded outside of Moria by Throin, rather than just losing an arm. And while the losses of the Dwarves are great, but they refuse to enter Moria because a) it isn't their home and b) Durin's Bane lurked within... you know, the Balrog.