I just passed my exam on Friday. I wish I would have made some notes in my DRG expert--I did not even open it during the exam, and found it generally un-useful to have, since I do not know how to use it. I pretty much just brought it with me because I could. I brought a drug book too, but did not even open it.
There was not really one particular area that I thought was more challenging, the questions I missed were spread evenly across the content areas. I have a clinical background in nursing, and have worked as a CDS for two years (the only one in a small hospital).
I thought there were a lot of tricky questions, and I am used to multiple choice, NCLEX style questions, I have taken nursing certification exams, and written NCLEX-style questions for competency assessment and nursing students, and volunteered on the NCLEX panel. I am good with this question style, but I found it difficult to know if I should or shouldn't read certain information into the questions on this exam. I would have benefited from doing more practice questions.
Good luck to all! If you have questions, my email is firstname.lastname@example.org, I would be happy to help if I can.