I don't like the Unofficial Guide, I find that I seldom agree with the dining reports, and some of the information seems hopelessly outdated. And the touring plans, get real! We tried them a couple times and always abandoned them after about an hour or two--either we had fallen totally behind, or they had us running like loons from one end of the park to the other.
The Birnbaums Book is too sugary as others put it, although the Birnbaums KIDS book is great for elementary kids making their first trip.
The Passporter book is IMHO the best of the lot, with the downloads you can access from teh site it's constantly up-to-date, the information seems to be the most practical and useful, and least biased. Plus thsoe passpockets are the best!
My biggest complaint about that book is that it seems generally geared towards the budget conscious, and doesn't do more than barely mention suites at the resorts, the spas, the Grand One, golf, V&A's Chef's Table, and some of the other "splurge" offerings.
Anne