Well Worth the Price.
I've purchased various supplemental books for Pathfinder, and have always been impressed by the quality of Kobold Press's releases. This book, I believe, sets a new level of excellence for other third-party publishers to strive for.
Intelligent and well thought out new classes. While I wouldn't necessarily be inclined to play some of them due to personal preference, there is no denying that they all seem remarkably well-balanced and well-designed. In particular, battle scion is (for me) a long awaited solution for the eternal Gish problem: creating a sword-and-spell base class that isn't over-powered, under-powered, or dull as mud. Theurge was a pleasant surprise as well. Savant looks to appeal to the DM who finds himself playing a PC again, and will likely keep people staying up all night creating persona and avatars (in the best of ways!). I think the greatest accomplishment of the book may be the spell-less ranger. I've never wanted to play a ranger with spells, and I've never been impressed by spell-less variants. This 1-20 class really nailed it on the head for me: options, flexibility, and more options.
The feats are a great mix of necessary tie-in feats for the new classes, and a range of other flavourful options. Having feats that makes using a sling a viable option in combat was definitely unexpected.
The archetypes were again very interesting and seemingly balanced.
The scaling combat feats are a great idea, something to slightly ease the feat-burden of melee and ranged fighting characters. The only issue I and my group had was with Two-Weapon Fighting, that seems to be perhaps too powerful a feat chain to be made a scaling single feat.
The book is very professionally done, excellent layout, and has attractive artwork.
The Spells section was a little underwhelming. The spells themselves were not in anyway lacking, I was just hoping for more material.
There were very minor layout problems, in particular in the feats section. While it was mostly in alphabetical order, there were a few misplaced feats. This is a superficial nitpick more than anything else.
Conclusion: 100% this book is worth its price. The new classes are its main draw, and they alone are worth the price of the book in my opinion. You know you have a great product when you struggle to think of any negative elements to write about. I highly recommend this product, and hope to see more material of similar quality soon both from Kobold Press and other Third-Party publishers.
[5 of 5 Stars!]