I thought it was a solid big screen adaptation. It missed some of the intricacies of the book but overall was able to portray the general themes and concepts of the novel. There were certain characterizations of which I wasn't a fan (Yueh role being more of a bit part, Jessica crying multiple times). Outside of that it was well written, well shot and well acted. I particularly liked the way he showed Paul seeing the different potential paths of the future.
Also the invasion of arrakeen was spectacular, the visuals conveyed the intimidation of a combined harkonnen/sardaukar assault very well. One particular aspect I liked was the Baron. The combination of the suspensors and the long flowing robes (while not quite in keeping with the books) gave him an almost vampiric quality that looked, to me, like an attempt to use his weight gaining disease to add to his overall intimidation - making him more like a living figure of myth for his subjects.