SPOILER ALERT for anyone stalking this conversation:

Chani is a lot more passive and uncritical in the novel, and I really like what they did with her character in this. The other major change is that Alia is born (and indeed kills the Baron), but they are obviously saving her for Dune Messiah. I think that change worked too.

There were other changes, but I won't bore you with those (sorry, I'm assuming you've not read the novels). :)