I'm really impressed. This may well kick my GMing up a level all by itself.
It actually reminds me a lot of the way the Design Patterns book improved my C++ design skills. Just reading it once added noticeably to my skills, and practicing the skills that it showed and rereading the rules gave me a lot of momentum for improvement.
I'm currently actively trying to understand the players I know in terms of Robin's character types. It's not completely obvious, but prvides useful guidance.
One down side: it is a lot of money per page ($10 for a 32-page book.) But I have no regrets about buying it.