I just got back from the exam. Passed on first try with Above Target in six domains and Target in the seventh. I used the PrepCast course and exam simulator as well as the Mike Griffiths book to study at my own pace. I took all four PrepCast practice exams and got an average of about 73%.
The test is tough - almost every question was situational. Questions are similar to what you see in the exam simulator but different enough that you have to think through them carefully. One thing I noticed is the use of certain key words to help you find the answer. Like if the question mentions "waste" then the answer probably has something to do with value stream. Read the questions carefully.
The PrepCast and Griffiths book are good sources on their own but they make a great combined resource. I took notes of the PrepCast videos, read the book and took notes, then focused on the exams and especially the quizzes where I would 10 questions at a time. I started studying/reading in September so obviously I took a lot of time to study and prepare.
My test idea was to go through the exam answering any questions that I could quickly. If I couldn't, then I'd skip it and move. Then go back, answer the remaining questions. At the end of that I went back through all of the questions. I only changed 5-6 answers the second time through.
