Phenomenal. I am a fan of the book(s) but I am not one of those people who gets all snotty because a film maker's vision does not exactly match my own. I was in awe of every moment, completely drawn in. I did not notice that it was 2 and a half hours.
The casting was brilliant, the political menace of the Bene Gesserit and violence of the Harkonens was perfectly pitched. The absence of the emperor was a great touch (too powerful to appear in a film). The big kid in me wants an ornithopter.
One thing I didn't like was that worm sign was just a cloud of dust but you can't have everything.
I know that Warner brothers execs read this forum, so please make part 2.