I took Kaplan's course just a few months ago, and took 7 CAT tests. All 7 of my tests ranged from 570 to 690 with them slowly trending up (almost a perfect upward trend). My last CAT was a 690 about 5 days before my actual test, and then I scored a 710 on test day. I found the CAT tests to be very representative of the actual test. I found the Kaplan CAT Quant to be slightly easier and the verbal to be slightly harder than the real thing. I would encourage you to study the
OG 12 as you get closer to your real test date so that you are familiar with what real tests questions will look like.
Overall I was very happy with Kaplan's on-site (non advanced) class. Good luck!
Also, don't put too much stock into the low,med,hard questions. They really don't mean anything, because each persons ability is different. For instance, the GMAT considers Geometry and Statistics to be "harder" questions, and so does Kaplan. The problem is, I LOVE Geometry and Statistics, so when I got those types of questions they felt easy. Number properties on the other hand often threw me for a loop. Most likely those levels are based on what % of people get them right, but that doesn't mean that they aren't easy or hard for you. Your job the GMAT is to get EVERY question you know how to do, right. It doesn't matter if it is hard or easy. Forget about the easy,med,hard designation, I know its tough, but trying to figure out the Kaplan Algo is not going to help you. I tried figuring it out, but I never did. But it turns out that it was very representative of the real thing. So just trust. Congrats on the 710! If you want the best estimate of what your real score would be, I would recommend the GMATprep software from
www.gmac.com (free).