Well, I've looked at this site for a while, and it's the first time I've seen the book. Usually they're selling a liquid - light type emulsion.
It looks interesting, but I'm holding out for PE. I think that his is written, not suprisingly, more to the audience that this forum represents. If I had $150 I'd rather blow on a book than a lens(es), chemicals, or restoring my car - I'd totally buy it.