Here's my opinions of the guidebooks (I think I have them all.)
Birnbaum - Easiest to read. Not much detail about resorts, but better than the Unofficial Guide. Lacks info about many attractions.
Unofficial Guide - Only for vacation commandos. The resort information on room location is good, but is seriously lacking any details about the resorts themselves. Good attraction information, but the book is just too much for anyone wanting an easy to read planner.
Frommers - How this book gets published is a mystery to me. It's horrible, opinionated and lacks any useful information.
Fodors - Tries to be detailed, but contains many mistakes.
Complete Guide To WDW - My favorite. Has great photos of all the resorts, rooms, attractions, and just enough information about everything. You can tell this book is written by fans of WDW, while the rest seem to be written by travel "experts".
Passporter - 2nd favorite. Has very useful details about all the resorts and attractions.