The audio book of Dune utilizes what should have been a great conceit: actors speak the parts of the main characters! Except that often, they don’t. Much of the book is narrated by one man, Scott Vance. Vance has to use his own acting skills to conjure up voices for the principal characters, and I suspect he was not given access to the other actor’s voices. His own imagination differs far too much from the actors we hear. The worst casualty is Paul. He is played by a fine actor with a teen-aged voice, but Vance speaks Paul's lines pompously in a middle-aged voice. The Baron Harkonnen is another casualty, acted in a rich, African-American voice that seems poles apart from the way Vance speaks Harkonnen’s lines.
Vance is British, and he narrates Herbert’s prose with an inappropriate British accent. None of the actors use the same accent. The contrast is vile.
One of Frank Herbert’s stylistic quirks might have remained hidden if Scott Vance did not unearth it: Herbert has unintentionally written a few weak, Shakespearean sentences, similar to this (a made-up example): We must resolve to change the awful thing. Vance makes such sentences sound like they belong in Shakespeare's plays.
The audio book did correct a mistake in my own pronunciation. I thought to pronounce Muad’Dib as: MOO-ahd Dib. Apparently, the author intended: m’WAD Deeb. All the actors pronounced the word that way.