The first two practice exams seemed to have way harder questions than was on the actual exam. I decided to take the last three practice exams and those seemed to be more reflective of what I experienced on the actual exam.
Edit: One thing I do wish that the folks at Whizlabs would do more of is explain why the wrong answers are wrong. During the review, I have seen this in some questions, but not for all. I have found this extremely helpful during my studies, even when I get the question right.