I waited a while before reviewing so I could rewatch the 2 recent Dune films.
These prequels are excellent - set 10000 years before the films. Technology has been perfected to a certain level but then paused and maybe has even dropped a bit over the next 10000 years. This was a excellent feature, both the technology and society are stagnated and going nowhere. There are no external threats and closest to this was machine inteligence which was stamped out leading to the technological stagnation.
I loved the choice of actresses for the two leading Harkonnen roles as 20ish and 50ish year olds, they look so plausible as being the same people at different ages that I had to google to see if they are actually related (they are not). But the triumph of casting is a bit of a easter egg, don't want to cause spoilers but there is a big Atredies meeting and one of them is was clearly picked to be similar to Duke Leto in the films (although 300 generations apart) - a lovely touch.
On plot it is mostly politics and backstabbing which is fine but I would say that the world building and ambience is actually a better part of the film and you can see that serious money was spent on this.
If there is a series 2 then I will certainly be renting it.