Sorry Steve, I also don't like the cover.
The content and chapters of the book may be a great read, but to people unfamiliar with your site or PD, they may simply avoid your book because of the ugly design.
I think you'd be able to reach and help far more people with a more attractive design. Although the quote "Don't judge a book by it's cover" is true, unfortunately, many people do. In the end here, I think you'd be missing out on reaching a much wider audience (Such as convincing people why the "Don't judge a book by it's cover" quote is true
) by using this cover.