IMO kaplan tests are just OK. I found that the questions are not very similar to the original GMAT ones. ex. the SC are way shorter than you will find in the actual test. Because of this I was able to complete the verbal section 10 minutes before the time.
The quant section is not bad. Some questions are really tricky and the concepts are explained clearly in the solution.

I feel if you have the time then go for the test. I would not use this test in the final days of my preparation. There are many better test out there which are more worthwhile.