I just got it yesterday, and while some of the ideas are very interesting, the balance in some of the feats seems way off. For instance, compare these 3 feats:
Improved Defenses, which has no pre-req and gives + 1 permanent bonus to each of your 3 saves: Ref, Fort, and Will.
Martial Arts I, no pre-req, increases your Unarmed damage by a die type and gives +1 dodge bonus on all Ref saves.
Dodge, which requires a 13 Dex, and only gives a dodge bonus of +1 to Ref save against the attacks of 1 attacker per round.
Why in the world would anyone take Dodge from among those 3 choices, except maybe because of its feat tree? Personally, I think I would reduce the power of Improved Defense to a +1 each to any 2 of the 3 saves, and increase the power of Dodge by saying you may either get +1 dodge bonus against all attackers or +2 against a single attacker, chosen each round. That would balance things out a bit more.
Also, what's up with the Ithorian's sonic bellow attack? I'd never heard of such a thing before.