I have two....
The Unofficial Guide is an absolute MUST, because they tell it like it is. Anything you could possibly want to know about attractions, best days to visit, resorts, restaurants (good and bad) are in the Unofficial Guide. I read it cover-to-cover twice before my trip last month.
And then I like Birnbaum's, because it has that Disney magic all over and through it. I love it for the descriptions.
I read a description about an attraction or restaurant in Birnbaum's...And then I turn to Unofficial to see what they think. hehe