Listen with me

There are a couple of elements at play when it comes to evaluating an audio book: the story itself and the way it's narrated. 

As you might expect given the authors, Good Omens is a tight narrative with impeccable comedic timing. It's fairly tongue in cheek but isn't afraid to say something real at the same time. It also doesn't feel the need to beat the reader over the head with it's messaging. Characters are distinct, each with just enough complexity to be distinct without wasting words on unnecessary description.

Narration is almost more important in an audio book. I've experienced otherwise excellent books that were derailed by an awkward reading. The version I listened to was read by Martin Jarvis. As a Brit, Jarvis' accent is the right one for this story. And his timing was just about perfect. No awkward pauses between lines. He varies speed to keep us engaged. His voice is dynamic as well, conveying the right emotion for each moment. He does slightly different voices for each character, enough to be distinct without becoming a distraction.

All in all, I've got to say that this is one of the better audio books I've experienced. If you have any interest in the work of Pratchett or Gaiman, do yourself a favor and listen to Good Omens.