There isnt dragons in Lotr, they are differnt cretures called the nazgul,
Also compaired to the book the hobbit part 2 is completly differnt, there is almost no fightng in this section of the book, Peter Jackons has added in action secnes to make it similar to Lotr
Dont get me wrong the Hobbit part 1 and 2 are great cinematic peices but the book is better, I prefer Lotr but maby thats because I didnt read the Lotr books