GMAT Strategy

I recently took a GMAT exam but was not too happy with the results. Therefore, I've scheduled a test for May. While preparing for my previous exam, I took all 6 Manhattan GMAT practice exams (twice over) and the two CAT exams that one has access to through MBA.com. Therefore, this time around I am left with no practice CAT exams from these two sources. I was wondering if someone could guide me in terms of the next best mock exam resource. Is it Princeton, or Kaplan or a third resource. I hear that Kaplan skews the scores downward, while Princeton is easier. Can someone please offer guidance?

Much appreciated