It's out! I watched it! It's good!
The short of it is that Denis Villeneuve succeeds in translating the novel to the screen, and does so in a way that seems almost effortless. Partly this is because the narrative has been slightly adjusted: the political intrigue has been somewhat backgrounded to put more focus on Paul's relationships with his mum and dad. But I think this was a smart change, because that grounding ironically gives the film more freedom to world-build, now that it can be related back to the characters. It's actually quite impressive, how it spends a lot of time setting up the world and conflict— the world of Dune is still plenty complex, this has not changed— while maintaining momentum. Even if it takes a while for the story to "get going", it's never dull.
The only place the story stumbles is with Yueh. Specifically, how they handle his betrayal of the Atreides. I'll admit this is a tough thing to adapt, since his subplot is basically entirely internal monologue, and choosing to play it as a twist isn't the worst thing. But Yueh doesn't have enough screentime or presence in the film for it to land as a twist, and it just feels kind of random and kind of limp. I don't know how I would have handled it— if people remarked on his trustworthyness, it would probably be too obvious— but it still stuck out.
The only major issue I have with the film is that Arrakis doesn't look nearly hot enough. That's going to sound a bit nitpicky, but way it's shot— clean photography, the land a bright, pale yellow— doesn't evoke heat, which conflicts with how the characters talk about the place. The palace workers begin to close the doors and tell Leto to come inside, because the rising sun will soon make the outdoors unbearable, but it doesn't look like anything more than a bright sunny day. It really needed a more vibrant colour, and possibly a hazy filter or something. What's funny is that Paul's visions of the planet look like that— so it's a little disappointing the rest of the film doesn't.
One interesting adaptational change: Jessica's motivation for having Paul. Now, the backstory here is that the Bene Gesserit are running a millennia-old breeding program to produce the Kwisatz Haderach, and the last step is to unite the Atreides and the Harkonnens. Thus the Bene Gesserit order Jessica to bare a daughter, so that she may be wed to the Harkonnen heir Feyd-Ratha; but she defies them and bares a son (Paul). In the novel, this is an act of love: Leto wanted a son, so she gave him a son. In the film… she thought she could bear the Kwisatz Haderach herself. This is certainly a change to Jessica's personality, and also raises questions about what she knew about the breeding program. Curious to see how this plays out in Part Two.