The problems are too difficult and full of typos. I really had higher expectations from Kaplan.Its great if you want to learn additional math skills but I only wanted to learn math for the Gmat.
However, on the slightly positive side, the tests are great for learning the pacing and format that the test will be in and knowing that is half the battle. Whatever you do, though, don’t trust the scores. The rumors that the Kaplan tests will score you 100-150 points lower than the actual exam are 100% true!