I liked the Birnbaum guide because it has lots of pictures, and really good descriptions of each attraction, restaurant and shop, including the type of merchandise at each.
I like the Unofficial Guide for the one- and two-day touring plans; they even have different ones depending on the ages in your group, and suggestions on how to blend the plans so that everyone has fun.
Both have lots of great information, and I would get both. I have not yet seen the Passporter guide, so I am curious what people think of it and if it's worth getting if you've got one or both of the others already...?