As other reviews have stated, this is not the most well written of books, and some of the plot holes are pretty hard to ignore. In particular the behaviours of the machine overlords and the idea that humans, reduced to slave status, would have any impact is a stretch. This kind of scenario has been done much better elsewhere.

However, this is the world of Dune and for those who loved Dune as kids, as I did, you'll find it easy to forget the difficulties with the novel and just enjoy the exploration of the Dune back-story and the origins of the complex society that Herbert described. For that alone it is well worth a read of any Dune fan, and I for one will happily work my way through the whole series.