Normally I'm a huge Paizo and Pathfinder fan. I've been playing and running Pathfinder since first edition and was keen when second edition was released.
This is a beautiful book. Sturdy, well lsid out, clear fonts, easy to read and no visible spelling errors that i've noticed. All the usual high Paizo production values that we've come to know and love.
For me the creature and NPC design rules (effectively the same thing in 2nd ed) are critical to run games.The rules are clear and seem well thought out.
However much of the rest of the book seems to be written simply to pad this section out into a viable publication. The gamemastery advice isn't revultionary or groundbreaking, the nation and settlement sections provide nothing mechanical and simply encourage GMs to lay out their information in the same format as Paizo.
On the whole I can't shake the feeling tha much of this book was written purely as padding for the sections surrounding creature, hazard and NPC creation and as a means to justify the $49.99 price tag.
This is the first time I've been left feeling disappointed by a Paizo release.