Good for high level quant or mid-level verbal

The quant section of these tests is excellent, with lots of unusual problems that improve your thinking skills. Occasionally they do spit out a question that contains material beyond what the scope of the actual test

The verbal section is not that useful for advanced verbal scores - say anything over 42 - because the questions are just too inconsistent and unclear. The "correct" answers in quite a lot of the 700 level SC contain a lot of badly written or even incorrect language/grammar. Some of the CR have 2 viable options in the answer choices or are generally unclear. RC is usually decent. (note that my verbal scores in official test prep are currently in the 44-49 range, so definitely at the upper end of the scale, and I don't have so many clarity issues in with the OG questions. OG questions can usually be pretty easily narrowed down to one answer choice and I don't find this the case with many of the 700 level gmat questions on this test)

If you are in the high level verbal range, these CATS may give you inconsistent verbal score depending on the questions they spit out.