I bought Path of War and this product, thinking that it would be the main book and the flashy extras. That this wasn't made clear in the product description of either, nor did it warn me that I was buying the same thing twice when checking out (and they were in the same shopping cart, no less). The name is a bit misleading, as well, because 'supplemental' suggests it adds to what you get already.
As for the content of the book, I really like how they fix a lot of long-standing problems in the game by providing alternative options, i.e. a Dex-to-damage feat and a better version of Combat Expertise that is competitive with Power Attack, but has bonuses for for sword-and-board characters rather than 2-handers. In the Archetypes, a few of them go against the core purposes of the class, but all of them look well-thought-out with effective class feature swaps.
