Whilst it might be a "favourite", it's not the "greatest" sci-fi film ever made (I'd plump for 2001: A Space Odyssey or Blade Runner) but is it something of a masterpiece nonetheless? I think so. It's my all-time favourite sci-fi novel, and I think Denis Villeneuve did a fantastic job. It's a must watch on an IMAX screen (I saw it four times) and really I shudder to think of anyone discovering this on television. I can't say I agree with you about it having no entertainment or rewatchability factor for the uninitiated either. The rest of my family (wife and two sons) all loved it, and they'd not read the book.

My original review is here, if you're interested. :)

https://medium.com/simon-dillon-cinema/film-review-dune-5f6c11b986b8