I like Dune. It has many flaws, which especially rankle where they are also departures from the book. The whole thing about using sound as a weapon, for example, undermines the book's notion of them having an advantage because their ethical stance gains the loyalty and fervour of their men. The plot is simplified to a ludicrous degree. Also, the special effects are shoddy in places.
What I like most about it is the characters, an aspect of the book I think the film captures perfectly. Also, the visuals are sometimes very striking and beautiful. The representation of the Guild Navigator folding space, for example, was brilliant. That's how it must have been. Also, some of the extra material, such as the early meeting between the Emperor and the Navigator, worked very well; as if the meeting had happened but got dropped from the book for some reason.