I have both Darrel's book (Kindle version) and Hogan's pdf book. I have gotten useful information from both. Thom is more technically oriented, and writes for a technically-sophisticated audience. If you are a geek like I am, you will learn a lot from Thom.
Darrel's approach is more informal and would appeal more to the average user. His preferences might appeal more to users who don't want to agonize over a lot of technical details or wade through a lot of theory. (That's NOT to say that his approach is to use the D800 as a point-and-shoot camera.)
I would really suggest you read both books. Each author's approach has merit, and you will find some nuggets in each book that won't be found in the other. Hogan writes for the pros and Darrel writes for the enthusiasts, IMO.