I got the book and have devoured it. Mmmm.
Legendary weapons seem neat, but they are, well, broken. The 'faith scion' feat gives you ... all the benefits of being a cleric. All of them. AND access to a legendary weapon. Uh, what?
Ok, being a druid and becoming a faith scion entails the loss of some skills, but still, full magic and special ability advancement. Bwuh.
Other things, like the domain wizard, similarly seem a little off kilter. People love armor as DR, but I'm not sure it works as well as people would like.
A few of the options, like spell points, have drastic effects that are hard to explain. This isn't an indictment... the book makes it clear that this, and other options, warrant caution.
All that said, man, there are some beautiful things in this book. The classes chapter, with lots of little tweaks, rocks.
I love the generic classes. They might work well for a modern game or some arena where I don't want quite so much crunch, but still want a solid D20 base. I think they'd work well for D20 CoC, for example.
I LOVE the Incantations (basically, make a bunch of skill checks to cast a very specific spell). Again, er, CoC anyone? Or similar genres.
The alternate XP system is very sensible, and skips a lot of accounting. I already have an alternate XP system which works better for me, but it was nice to see, particularly if I join a D&D game that doesn't use my houserule.
All in all, well worth the list price. (Though Amazon had it 30% off...)