My Kaplan CAT scores are as follows:
Low score 540
Mean score 600
High score 630
I have taken all of the Kaplan CATs, including the ultimate practice test (scored a 580 on that). I plan on taking them all a second time as well. I am going to save the GMATprep tests for closer to my actual test date.
I disagree with the Kaplan bashing. I have taken classes like Kaplan to study for my securities licenses and the same method is used throughout.
The practice tests are made much more difficult for a couple of reasons. The first (and most important), is for marketing purposes. Companies like Kaplan and STC (Securities Training Corporation) want you to be concerned with your low test scores in hopes that you will purchase a product/enter an expensive class. That being said, Kaplan and STC have proven year in and year out to yield the highest test scores/passing rates of any education training companies in their respective fields.
Believe it or not, applying the same techniques you would use to answer less difficult problems, to more difficult problems is going to allow you to correctly answer the less difficult problems with more consistency and efficiency (the two most important skills when taking the GMAT).
In any event, everything I am reading on the internet is telling me that I should expect 70-100 additional points on my actual GMAT when compared to my CAT scores. I have several friends who went through Kaplan and actually recommended the class to me. They all said that they picked up at least 80 points on actual GMAT. They also said the GMATprep tests are going to give you the most accurate assessment of what you GMAT score will be.
MP