This book has gotten a lot of flack for two reasons: (1) A number of people were upset by the large amount of errata posted after the book came out. (2) A number of people were upset by the perceived power-creep that this book carried with it, especially in the archetype section.

Both of these are reasonable complaints that I largely agree with.

That said, this book also contains a cornucopia of player options that are great fun. A number of the classes it introduced are now mainstream: it’s hard to imagine playing the game without options like the Brawler, the Investigator, the Slayer, the Bloodrager, the Hunter, or the Warpriest. Or to play without archetypes like the Bolt Ace (Gunslinger), Mutation Warrior or Martial Master (Fighter).

Moreover, the book introduced a number of feats that improve on the available build options available to most players (Extra Hex! Slashing Grace!). Likewise, although the spells in this book seem to have flown under the radar, there are a lot of nice and interesting spells are introduced in this book (Glue Seal, Communal Align Weapon, Wall of Blindness/Deafness, Wall of Nausea, Anti-Incorporeal Shell, Adjustable Disguise, Adjustable Polymorph, Investigative Mind, etc).

Easily 5 stars worth of good material here. Given the unusually large amount of errata, I feel compelled to deduct a star. But all that said, it’s hard to imagine playing Pathfinder without this book -- after the Core Rulebook and Advanced Players Guide, it’s probably the best book for players to pick up.