These are the two books I've purchased so far (I've also had a few free e-books, but more on them another day). As you may see from the bookmarks, I'm still reading these. I'm probably about half way through each of them at the moment, and I'll review them properly when I'm done, but so far I'll say this:
The Unofficial Guide: Walt Disney World 2014 is a godsend. I suspect if the info you need isn't in this book, you don't actually need it! I read quite a few reviews of this book myself before I purchased it, but I was overwhelmed at how BIG this book is (and the size more than justifies the price!) and how comprehensive it is. I particularly like the writing style, which is has a good balance between praise and realism. If it had been too "WOW", I don't think I'd have trusted it one bit. I love that they often show both sides of a particular point of view, with quotes from readers everywhere. Very impressed.
The Hidden Magic of Walt Disney World... not so much. I love the premise of this book, but so far have found it a bit of a slog. It might be marginally better if I was stood in the parks with the book in my hand, but I have no intention of touring like that. I want to travel light. If I remember some tidbits from the book, great, but a lot of them aren't as interesting as perhaps the author thinks, are freely available on the internet or simply aren't true anymore (it was published in 2009, and even without having ever set foot in a park, I know some of the stuff in here is completely out of date)... I'm not sure I'd recommend this one. I don't like the writing style at all, and find it very same-y. I'd skip this one, if I had the chance to.
I want to get my hands on a couple more books as the time gets closer, but these were my starting point. If you have any recommendations, do let me know! :)