I took it last year. There were 25 MC questions. 90% of 25 is 22.5, so it was unclear to me whether I could miss three or only two and still pass. They provided a binder with a printed copy of all the relevant laws.
My personal experience is that there was no need to study for this exam, and a couple of colleagues who also took it last year agree. I spent maybe an hour looking through the handbook beforehand just to familiarize myself with what was in there, but even that was probably unnecessary. The exam instructions were (not in these exact words, but pretty clearly), your task in this exam is to read each question, find the relevant law in the handbook, and answer accordingly (i.e., they do not expect you to have learned the information ahead of time). There is AMPLE time allotted -- I believe it was three hours, so more than 7 minutes per question. Many of the questions were worded in exactly the same language as the law. They also told us that if we felt a question was unclear, we could write our reasoning on the exam itself next to the question and those written answers would be "taken into account" during scoring. (I am not making that up, though I have no idea whether/how it actually came into play...) Out of the 25 questions, there were maybe 5 that I felt significantly uncertain about. I passed, no idea by what margin.
I suppose the exception to my statement that exam prep is unnecessary would be if you know yourself to be a slow reader or someone who has difficulty scanning through text to find the relevant info. I did have a bit of a headache after the exam from doing so much visual scanning through those couple hundred pages of Courier New font text to find the answers.
