Very loud and great visuals, but weak plot. I haven't read the novel, so maybe they just followed the plot, but either way, I found that parts of the story line didn't make much sense. Leaving aside the time worn trope of the white savior coming to redeem the backwards, darker skin people, and the evil villain who lacked any depth or redeeming qualities at all, the story generally was reasonable except for the end when the aged emperor, for some unimaginable reason, decides to personally accept a challenge from an upstart leader on a distant (though strategically important) planet by personally going to that planet to crush him. Why would the elderly emperor of galactic empire take such a risk when he could send his army to do it? Also, if anyone could become emperor simply by challenging the existing emperor, there would be constant challenges from the great houses trying to gain the throne. I found that glaringly irrational decision and nonsensical part of the plot difficult to overlook. And despite all the talk of Paul Atreides being some sort of messiah, he didn't actually do anything messianic except survive drinking poison. One final point: as much as I like Christopher Walken, he was terribly mis-cast as the emperor. I just couldn't buy it.
The movie was visually quite stunning in parts and the exploration of Paul and his mother's acceptance into the population of the desert people was well done. The battle scenes were really good and didn't look like CGI and the scenes of the people riding the giant worms were great cinematography. The music was way, way over the top. It was very loud and very dramatic, even in scenes that would have been better with more a more subtle musical background. I sometimes it felt like the soundtrack was overshadowing the actors.
On the whole it was enjoyable, though it didn't need to be almost 3 hours long. A passable, but not great flick.