Having read all the Dune novels I would say the original film is very dated now but the script is far truer to the books than the Villeneuve offerings. The original film covers the wealth of history around the different 'Houses' and should have been longer, which it was until it went into the cutting room. Some big names in the cast and well acted too, with wonderful costumes and sets. However, the special effects are of course poor by todays standards. Obviously a film can seldom compete with the novel it's based on but as far as I'm concerned the original still remains the best portrayal of the novels so far.
The Villeneuve offerings are wonderfully cinematic. In this respect he did a good job but so much of the fantastic story behind this film is missing. The original managed to get a large chunk of the story across in one film, Villeneuve has dragged this out to two and I can't understand why with so much of the story missing... probably more revenue!
Haven't seen the second film yet but I'll probably get it on disk when it becomes available. Part One for me was a let down and I can't see Part Two being any different. Both appear to dumbed-down action movies to me but I'm a Dune fan so I'll have to have it in my collection