I didn't use the book questions much, but the general consensus is that the online questions are easier than the book questions. As far as which one is most helpful, I would say that both are very useful, just in slightly different ways. A more challenging questions will teach you more, so from that perspective, the book questions are great. The actual exam will pull material from all over, not just 1 chapter at a time, so I feel like the online test bank is useful for emulating that experience, if you use random questions sets (whether through Practice Session, which was my favorite, or through Quiz or Practice Exams). In my opinion, the actual test questions are closer in difficulty to the online test bank than to the book, so I think that the online version also gives you a better feel for timing and pacing yourself and because the questions are a bit easier can help you learn to move through them quickly.
Personally, like I said, I didn't use the book much…for the simple reason that at the time, I didn't have somewhere I could sit down with book, paper, and pencil, and work out problems…and that I struggled to not fall asleep sitting somewhere with the book, whereas the computer and the instant right or wrong kept me going better. I also liked the instant right or wrong which is harder to get with the book (if I check the answer to 18, I'll see and process the answer to 19 before I even realize I've found the answer for 18 – not good 😛 ). However, the book's questions were more challenging and would, I'm sure, have been quite helpful, if I'd been disciplined enough to use them! So I would encourage others to use the book questions even though I wasn't a good enough student to do so. 😛
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