I cannot speak to teaching it to an initio level, however I have used that book and his second: "flight discipline" in helping to maintain my company course.
I've found that much of the content is similar to other manuals from a CRM aspect; it's his explanation of judgement/decision making that we have taken on board. I actually just finished teaching an initial CRM yesterday and when I got to the part where we use Kerns ideas the pens were flying to jot down notes, which tells me the relative importance of the concept others see in the material.
I'm actually looking to put more of his concepts into the course as I've personally used many of his methods in my normal line flying position and have found them to be quite adequate.