The feats and prestige classes herein are put together incredibly well, full of flavor, and not lacking in the power department either, I can already see multiple parts I would like to use on future characters, from the Dawnflower Anchorite and its ability to seamlessly integrate class features from multiple classes into one, to the Runeguard, an awesome take on the Thassilonian runes we were teased with in Rise of the Runelords and other AP's (and whose capstone is about as bonkers as Batman's utility belt).
But probably the most important part of this book is a feat found within the first few pages, Prestigious Spellcaster, which has single-handedly saved dozens of previously published prestige classes from obscurity. I wouldn't be surprised if it sees as much use as classic feats like spell perfection. It's really a game changer!
They still haven't addressed clerics being among the worst channelers, which I had hoped for in this book. But I was in no way disappointed with my purchase.