Best in the business !

[Quant tests review]

For Gmat quant, you do not need any extra practice besides what the GMAT club tests provide. You will get upwards of 25 tests that are more than ample practice. In addition, you also get super useful analysis( weak areas, timing, how others are performing). My weak sections were inequalities and absolute values.

Deep diving, I would also say that the 600 level questions are more like 680-690 level. Extremely useful practice. No prep provider comes close. The questions generally are on the tougher side. Questions here test 2-3 concepts per question whereas the real GMAT/GMAT prep tests 1-2 concepts per question.
The real learning lies in 700 level questions. Quite a few questions are of the >750 level. Questions are pure class. A lot of thinking has gone behind each question.

Long story short, do all the tests, analyse each question, repeat till the concepts are 2nd nature and a score of >Q48 is assured. Put in alittle more effort a score of Q50-51 would not look so difficult.