It doesn't take much snooping around on the internet to find a ton of opinion articles about how the new Dune movies are so much better (than Lynch's old Dune) because they follow the book more closely. The point that they follow the book "more" closely... prob true. Are they better? I think that's debatable.
I love Lynch's Dune for a ton of reasons. I think it's visually a masterpiece. And in the ways it does follow the book, it does a nice job. What I mean is, watching the movie and looking for cool little subtle details yields wonderful results. The cast is excellent. And it does some things right where the new movies fail... I'll get into that.
The new Dune... I like the first one (haven't seen the second one yet) enough. I do think it's a bit of a snore fest. It doesn't feel like they had enough material to fill the runtime (an annoying trend with lots of films ever since LOR). But that's to be expected. The cast is very good. And, if one were to do a side by side comparison with Lynch's Dune, it prob does follow the book more closely.
Ok. Now for the parts that some people might get grumpy about...
First, the use of shields. Admittedly, this isn't done visually great in the Lynch version but at least they work conceptually truer to the book. Which is a truly interesting take on shields and a significant aspect of the Dune universe. How shields work guides how combat works. The trilogy of ballistic weapons, shields, and laser weapons is sort of a rock, paper, scissors of military strength when combined with the politics of the world, making for interesting power dynamics. Without having shields represented properly completely cheapens the Dune universe in ways I find unforgivable in the new movie. It was pure laziness, how they handle this, and a missed opportunity. We could have had unique combat scenes, taking advantage of modern film special effects techniques. Instead we got video game reminiscent shields that are nearly pointless, with generic combat that is beyond boring to watch. Just terrible. This is such a major fail in the newest Dune, I would say it ruins the movie a far as following the book is concerned. Maybe harsh, but they had a chance to do this right and chose not to.
Next... the Harkonens. In the book and in Lynch's version they're truly horrifying. Beyond being cold blooded killers, we get a sense of their culture of being inbred, sadistic, and racists, and led by a pedophile in the Baron. And we see how truly power hungry the emperor is to be willing to side with and work with these people. (I mean, the emperor is plenty horrible in his own ways... Sardaukar?!). So, in comparison, the new movie Harkonens are a clown show. Barely a better rendition than the sci fi channel take on them (at least being made for tv and low budget... nobody can mind them being this way in that version). BTW, I think the sci fi channel Dune is worth seeing... a story for perhaps another day.
In the end, I have no real problems with the new Dune. I'm glad it exists. I find it annoying that so many can't stop gushing about how it follows the books when it definitely gets major things wrong. (But at least they did make the ornithopters look cool!). Decent movie. Worth seeing once. The Lynch version, though, truly memorable. Flawed for sure, but worth seeing. And I think a better overall movie. I enjoy it over and over. The visuals alone mean at least it's not gonna waste your time.