Really boring for someone who doesn't hasn't read the books. I went in not knowing anything about the DUNE universe, and I went out still not knowing anything. Everything is just so confusing and the pace stays really slow for the entire movie with nothing exciting happening, I almost even went to sleep during some of the scenes. Imagine having to sit through 3 hours of emptiness and confusion. Yup, it was torture. I get some people like these types of movies, especially the ones who know something about the universe, but it's just not for me.
One extra star for the music and visuals.