I wrote this a while ago and still stand by my opinion:

I personally believe that Kaplan tests are not necessarily harder, but more academically oriented, so to speak. Kaplan focuses on the straightforward math problems, while the GMAT also hits hard with some pretty nasty word problems. It all depends on your general taste for different problems.

My own personal experience with test scores is as follows: the free test is greatly skewed in quant. I got only three mistakes but still scored way below what I was supposed to get (can't remember if it was 46 or 48), since something like three days later I took another Kaplan test, had three mistakes but scored 53... While most of my scores in Kaplan were around 740, I did also get 800 on one test, which kind of made my day... But again, it's a personal view.

As you can see, I had roughly the same experience as you did with the first test (the free one). The rest of my scores hovered around 750 or something like that, with the exception of that 800.

One final note: Kaplan CR is not quite GMAT-style, IMHO. I'd often find myself "in an argument" with the authors with regards to their answers. This almost never happened with the OG - their answers were crystal-clear and indisputable.

Are you guys speaking about the CATS which come along with the kaplan Premier CD or the online one's?

There's a free online test plus another 4 tests on the CD. However, since the CD is not working on Vista, I asked them about what I should do. They told me that the 4 tests on the syllabus are the same as those on the CD.

I'm taking the Kaplan GMAT class so I was referring to the 9 CATs Kaplan offers online. I would assume these are similar to the ones in the book but not 100% sure