The book is like one huge monologue. It's not very entertaining. The main character mostly talks about how awesome he is and how everything he does is for the better. While this is all well and good reading the exact same sentence repeated over the course of 400 pages is not.
Taking place thousands of years after Dune Messiah Leto II is still alive and is now considered Emperor/God of the empire. He physically looks much different now as he excepts the bodily changes of turning into a sandworm. His body and mind still hold on to some human things. For one he keeps bringing Duncan Idaho back to serve him, Duncan keeps the unhuman part of Leto at bay. Most people under Leto do not agree with the way he runs things. Many want to overthrow him.
I find all the characters in the Dune Universe are so different and interesting in their own way. My favorite character in this one was and is Duncan Idaho. I wonder how many times Leto had cloned him or how many of Duncan's children or grandchildren ran about Arrakis.
Not much is explained as to why the golden path leads Leto to become a sandworm or why all the worlds will go downhill when he is gone. There are many questions left unanswered but I can let some go because real-life leaves questions unanswered.
I will continue to read the rest of the Dune series. I think fans of Science Fiction, and Family Sagas will enjoy this series. I say this as a fan of lite Science Fiction, I don't like SciFi books too heavy and all science jargon.