I didn't use the Petersons online, but I did use their book, both the study material and the sample exams. Their sample exams are IMO much MUCH more difficult than the actual exam. I posted my thoughts about this exam in another thread called College Math --Don't Sweat it -- or something like that, in much more detail, please take a look,
My overall take is that all of the topics in the overview are covered, making this kind of a broad test, but they're really lightweight examples, making it not very deep, and IMO an easy test if you have a decent grasp of the principles.