the white book is more detailed, and in some cases, over explains things. I personally think it is a better study guide. It also has those end of chapter quizes, which are great. Other than that, they are pretty much identical.
The "White Book" is the one Kaplan gives you when you enroll in the class. The "Blue Book" is a stand alone book. The "Blue Book" has questions that are in the "Classroom Book" that goes with the "White Book."