The paper book has a few extras. Some slight re-writes, added details and explanations. But, coolest of all, a glossary!
Why do I think a glossary is so cool? It is the definitive sign of a great classic sci-fi book. Wanna know if a book is a good sci-fi, a classic? Open up the back cover, and see if there's a glossary. Problem solved.
If you followed some blog-link into here, the links to both versions of my book are one step up this site's tree, on the Home page.