I was introduced to the Unofficial Guides series about 20 years ago and have been a fan ever since. If I'm making a trip to anyplace that has an Unofficial Guide, I read it ... because I know I'll be getting the proverbial straight dope.
This includes places I've been to before, like Disneyland. Why? Because the parks change things from time to time, and that means changes to traffic flow, prices, menus and more.
This time, I admit to a very quick and specific read; I'm planning a single-day trip to Disneyland alone for the 60th Anniversary events. That means I deliberately skipped the (very useful if you're going) sections on California Adventure and Universal Studios Hollywood.
If you are going to any of these places for the first time, you are crazy *not* to get this book and follow the advice -- as well as yanking out the touring plans and sticking them in your handbag or pocket. Going to Disney without some kind of plan is nuts! Even though it seems like a lot of extra walking, the plans really do save you hours in line.
Get it. Read it. Live it.