2.5*
In a word - weird.
An enjoyable read though a book of deep contrasts, often within the same domain.
By this, I mean parts of the 'universe' are deeply thought out, interesting and inventive (the planet Akaris). While the rest of the universe is basic at best. Indeed I think this would be a better medieval type fantasy book.
No need at all for other planets or the few uses of 'science' fiction. Especially if you don't read the appendix. Without that explaining the lack of some technologies you are left grasping about asking why are there no computers yet a hyper rigid honour bound medieval class structure?
Some of the characters are equally well illustrated - especially some of the women, a pleasant surprise after reading other 'classic' sci-fi (I'm looking at you Asimov with 'Foundation').
But then again our hero cannot have a standard loss growth and revenge arc - he has to become super-Jesus in the process. Foreseeing and forecasting the future, woe is the heady weight on Paul's privileged shoulders. Apart from that aspect the other confusing religious aspects are weird yet fairly interesting, but as above unexplained until the appendix.
Some of the battle scenes, both one on one and between ducal armies belie the books age, as do many of the distance and time issues when talking about space travel. It makes little sense to yarn on about an army of Freemen rampaging accross the universe. Again, better if this were a fantasy book on a single world.
Overall, happy I have read it but I'm not lining up for the rest of the series, it's better than the Asimov book I've read, on par at best with Heinlien. You can see where the cult following developed cool (worms, spice, dust) but its age and flaws are clear.