I have, and have used, both versions of Camera To Print as well as the LL's tutorial on LR4. I bought "The Digital Negative" to help my wife get the most out of ACR, and I decided to have a look through it before giving it to her.
Well, I started with the first page and so far have gone page by page through the segment on sharpening and noise reduction. My wife will not see the book until I have finished the rest of it. Thanks to Jeff's explanations...the "why" behind the "what," I have finally ousted my older ways of thinking about seemingly self-evident controls such as Contrast, Highlights, Shadows, etc, and reorganized my way of working with my pix.
While Jeff's sense of humor is evident throughout the book it does not become the "tail wagging the dog," and his purpose of giving enough technical explanation at each point remains prominent. I'm a person who can grasp needed concepts yet can also find myself swimming (more like drowning) if things get so technical that my eyes cross as I read. Jeff has hit just the right level of technical discourse so that I understand his points and methods in LR and ACR.
So far, the few notes to me I have written in the blank pages at the beginning of the book have made the book well worth the cost.