As I mentioned before, I don't have the book. The video is, in my opinion, a must (to actually "get" the idea). If you are looking to get the best info, but perhaps not have to spend $20 on both (i.e. you want to pick one or the other) -- I'd say go with the video.
This thread is actually helpful to me, also. I'm close to getting one of their systems because the Sharpmaker I have doesn't do things quickly enough for me. Fantastic for touch ups, but not fast enough for reprofiling, etc. I was gonna buy the book, but now I think maybe I don't need it...?! Watching is probably better than reading - less likelihood of misinterpretation.