I picked up this book today ( SSS's Advanced Player Guide ) and would be glad to answer questions. I haven't read it yet ( just glanced through a bit ), so I can't offer any informed opinions yet. Yes, this book is firmly in the Unearthed Arcana, Occult Lore ( ATLAS )vein. 200 Pages - large type. Lotsa White Space...
To expand on what Tumbler has already written, here is an incomplete table of contents:
Chapter one: Character Options
Heroic Merits and Tragic Flaws ( A list for each primary ability )
Racial Class modifiers ( minor skill bonuses for specific races by class)
Chapter two: Character Classes
New Prestige Classes: Dilettante, Elementalist, Gallowglass, Gemcaster, Pit Fighter, Sidestepper
Elite PrC's ( level 12+ to qualify ) Arcane Warrior, Plantmaster, Rogue Hunter, Temporal Mage, Undead Bane
Epic Levels ( Progression tables and class feature descriptions for all core classes to 30th level )
Chapter Three: Alternative Combat Rules
New Initiative Systems ( one uses playing cards! )
Critical Fumbles
Alternative Combat Rules (Phased Combat, Weapon Speeds, Armor Damage, Combat Defense )
Wound Level System
Detailed Critical Hits ( detailed tables by weapon type/body location )
Chapter Four: Arcane Spellcasting Systems
Mana Based Spell Casting System ( point based system - points vary by class and there are daily bonus points for relevant ability score bonuses )
Skill Based Spell Casting System (also does away with spell/day slots - utilizes new skill: "Spellcasting" DC raises as spell level increases )
Spellcasting Critical Succeses and Failures ( detailed random effect/result tables tables by spell school )
Chapter Five: Variant Magic
Aethercraft ( new 20 level class, Aethersmith - They make magic powered devices - multiple active devices/spell level )
Animism ( new 20 level class, Animist - Alternate Druid type- customized divine spell list )
Geomancy ( new 20 level class, Geomancer - casts earth based elemental spells )
Soulcrafting ( new 20 level class, Soulcrafter - steal others personality & identity - divine spell list )
New Spell Lists ( for classes above )
New Spells ( mostly aimed at new classes from the same chapter )
Chapter Six: Castle and Keep
Creating a Community
Here is an incomplete sample from the book - each category is explained in detail:
Ashcrest
Community Type: Military 1/Civilian 1
Popoulation Level: 2 ( 82 Adults )
Force: 13 (+1)
Mobility:
Resilience:
Learning:
Awareness:
Command:
Wealth:
Defense Bonus:
Reputation Bonus:
Skills:
Feats:
Description:
Benefits:
( edit: added more detail )