I am not as far along. I purchased the full set of six books a few months back and just started in on Dune Messiah. I remember when I was much younger feeling that each book, while still really good, were each a step down in enjoyment for me from the previous. I generally have mellowed in opinions and am hoping this is the case here.
And after finishing Dune, I am kind of surprised by how lightly the book went into characterization - each character seems to exist as a set of qualities, without a great deal of inner life or thought, even Paul. The book itself seems to be written as a history, which may be an artifact of the time it was written and I may just be used to much more descriptive, even flowery, prose from more contemporary novels. Still, I did really enjoy the obvious care and thought put into worldbuilding here, and I know there’s much more to come in future books, so I’m looking forward to making my way through them.