I found that with the Kaplan tests the PS and BS sections were harder. To compensate this fact, they made the curve much more generous (usually you could get 6-8 wrong and still obtain a 14). The AAMC tests are much easier but the curve is harder.
I'm not sure they transfer, but I felt that the Kaplan tests were slightly inflated. My AAMC average was 36, my kaplan average was around a 38. And for my actual exam... well I won't know how I did until the 13th of october.
There aren't that many posts, but the poll got a good number of votes. One thing to keep in mind is that Kaplan's verbal is not representative of the actual MCAT.
Why is Kaplan's verbal bad?
Kaplan is bad in verbal because it doesn't stress the same things as the actual MCAT. For the MCAT, the main idea and author's point of view/opinion are the keys to success. Conversely, Kaplan focuses more on the detail oriented questions which are easy to teach; the kind of questions which make you go back over the passage to find the minute detail being tested. On the MCAT, going back to the passages will kill your timing. Furthermore, you rarely receive such questions and when you do get them, they can typically be answered with the main idea or author's opinion.