As a Dune (the books, and Frank Herbert more broadly) superfan (I cannot tell you how many times I've read the entire series), Dune Part 2 is deeply satisfying, thrilling, and perfectly cast. Finally we have the movies we've always wanted.
While parts 1 and 2 could actually be slightly longer and cover details of the Landsraad, the metabolic importance of melange, and the Guild and navigators, it is probably most broadly appealing as currently released.
Director's cut, anyone? Sign me up!