The only book I felt confident enough to pre-order. Thankfully, I wasn't dissapointed. There's lots of excellent stuff in there. Pretty much all of the mechanic stuff in the book was great, even if I don't plan to use it personally.
My only major compaint is that the first half of the book was overly fluffy, especially in the expanded class options. The options were great, but all the descriptive text about the class was uninterresting. There was a little bit to much inlcuded with the new classes as well, and even the feats seemed to have more flavor text added.
The fluffies in the 2nd half of the book however are excellent. I liked the character and party personality/background building tips. Nothing overly specific, but just enough to spark lots of other ideas.
The character rebuilding stuff I'm sure is fine, but our group handles it by DM approval just fine so we probably wont be using it. The organization rules are intriguing, but their example of play with the various opposed checks seems cumbersome in game and would be better handled behind the scenes a head of time, or simply at DMs discretion.
The quick creation Appendix is possibly the best thing in the entire book, and probably the most useful. I've been waiting for one of these. Definately speeds the process for NPC creation.