My Review

Maths Tests:

The GMAT Club Maths/Quant tests just as every other person on the forum states, are pretty good. I would not say that the questions are extremely difficult, but rather that some of the questions are of a really good level. The good part about the tests is that there are a lot of 700+ level questions which makes the tests overall may be a little more difficult than the actual GMAT.
These exams if properly practised will help you improve your score.

Verbal:
I found the verbal tests to be not exactly in line with the actual GMAT. My scores were also not consistent. Ranging from a mere 24 to a 38, whereas my scores on the GMAT Prep exams has been pretty much around 37-38. So there might be a lot of people thinking that their preparation is lacking, just because they scored less here. But it's not a true indication of the actual score you will get. So just practice these questions and look at the solutions.