But it also draws from the LOTR appendices and fleshes out stuff like the White Council vs the Nefromacer that took place "off page" in the Hobbit book. So it's far more than just the 300 pages of text.Probably cause LotR was 1500 pages shrunk to 3 movies, while the Hobbit is 300 pages stretched to 3 movies..
Personally, I liked the hobbit movie a lot. Not as much as the LOTR movies, but still thought it was a great flick.