The Permanent Damage optional rules are interesting, but we haven't used them in our games so far.
There are some interesting new feats and combat maneuvers. The new weapons, armor, and other equipment are ok. Some of the weapon and armor modifications are overpowered and/or silly. I'm not sure about the Monastic Scholar options and the new skills.
What I like best are the alternative class features for all classes. Imo Fighting Frenzy is better than Rage for the Barbarian. I play a rather martial Temptress and took both Temptress ACFs from the book and another player took one of the two Pirate ACFs.
The Martial Disciple class from S&P 30 is reprinted in the book and I like it.