just read the synopsis of both films and you'll see that there is very few differences between the films, if the films were two students in an exam they'd be chucked for plagiarism, that is how similar the films are.
And Avatar is Pochahontas in space, and Harry Potter is the Hero's Journey-principle all over, and all of H.C.Andersen's fairy tales were copies of old folk lore and spoken fairy tales, just like the Grimm fairy tales, not to mention Lion King and Hamlet and Kimba and DEEEEEEEEEEEERP!!
I don't care of that way of speaking. It makes up for nothing at all besides the stories sharing an overall plot. It does not consider that that plot might be shown in a drastically different way, that the story might be made appealing differently, that the characters will shed a different light on the story, that the outcome might not be sum of the same parts.
And no, I haven't watched either movie, but I do have respect for the fact that someone has been able to write (and film) a known story in a way that compel it to a modern audience, to the point of it getting quite the fanbase. Just as I respect the fact that Meyer has been able to write a story that has drawn what seems like the majority of a female generation into the threads of romance and the supernatural. Before Twilit, only Harry Potter had made fantasy an acceptable setting, and urban fantasy was never touched upon.
Now I just wish the rest of the authors would stop copying Twilit, but, I guess I can't have all.
Didn't watch, didn't read, it's not my preferred genre so I won't try and read it. I have heard a lot of good things about the movie and its relation to the book, however, and it should be worth watching, whether you are a fan or not, according to both family and friends who have watched it.
As for anything that might have changed between book and movie, well, movies are a different medium, and it is often difficult to portray a story visually, when it is formerly only in text. Any changes might have been either sacrifice or directly changed to fit what might or might not be planned for any further movies, should the current one be deemed a success.
It went well for Harry Potter, for example, and I doubt people, who have taken such a care to follow the story of the book would make stupid mistakes that will negatively affect continuity in future productions.
And that was a lot of rambling, and I have no idea what I am saying, so prolly listen to them other peoples.