Passed the exam at ReInvent on Nov. 30 with a score of 81%. I felt very well prepared with the help of the whizlabs practice tests, in combination with the ACloudGuru course. I myself did not concentrate much on whitepapers or presentations - I find those so dense it is difficult to find the pearls within them. My advice is to concentrate on a targeted course and the practice exams. Once you have digested a course and can consistently score 80+ on the practice exams you are ready.