I just took and passed CIA Part 3 this past weekend (6/7/14). I wouldn't say it's so much difficult as it is what you mentioned, information overload, especially since Parts 1 and 2 combined have less information.
I personally used Gleim. I had access to Learn CIA from the IIA, but I'm not a fan of how their books outline the information. I understand that they have it set up in sections like the exam itself, but I like how Gleim breaks it up a little bit more.
Anyway, this was my 2nd time taking the exam. I passed parts 1 and 2 within 2 weeks of each other, and studied for part 3 for about 3 weeks. I wasn't doing that great on the practice tests, but still took Part 3 back in February and got a 586, which is basically me getting 1 or 2 questions wrong from passing. I waited the 90 days and took it again immediately, studying again for about 3 weeks total, but you'd be amazed at how much you pick up again from what you understood, and how much you had no idea you missed completely when reading the books. Those were the intangibles right there. There weren't too many practice questions that were identical to the actual exam, so just like everyone says, make sure you understand the concepts. Obviously every exam is different, but despite me trying to memorize every accounting/finance equation, I found that on both exams that there were very few accounting and finance questions. The equations they did have were actually very simple, which made it easier and quicker to move on. I'd say that the topics to focus on would be Organizations Structure/Business Processes and Risks, Management/Leadership Principles, and IT/Business Continuity. I wouldn't discount any of the other sections, but these are just the one's I feel like they focused on when I took the exam each time.
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