Lots of really cool information and wonderful, flavorful player options. My only real criticisms are 1) the Bone Knight has some confusing, unintuitive mechanics, and 2) the way the book is laid out, you have to dig through page after page of fluff to find the actual mechanics, rather than having, say, all the subclasses in one section and all the class fluff in another.
Most of the book is basically official-level quality, though. Definitely worth the purchase if you're looking for more options.
[4 of 5 Stars!]