I am planning on reading his book. There is absolutely no way in hell that I could ever do my current job on 4 hours/week. But, I expect that there will be at least a few things in his book that I can use to become more productive, or use later.
I also read the GTD book by David Allen. I don’t use the GTD process religiously, but I did get several things out of the book that have helped me become more organized and productive in one way or another. Nothing revolutionary, just helpful. For the few bucks that the book costs, I highly recommend it.