Properly made

I have taken several Gmat club's CATs, mainly Quant.
I found the questions a bit hard, but not as hard as I imagined when I was viewing the reviews of other members.

Anyway, what I liked the most about gmat club's CATs was the scoring algorithm, which in my opinion is close to the real test's one.
Questions from all levels.Thats the key. In the real GMAT test even if you are solving correct the majority of the questions you will not only get 700+ lvl questions but also 500,600 etc.

The explanations were quite good, and I think these tests are nice for those who want to reach the upper 40s or even 50s in quant.

As for the verbal section, it was quite good too.
Nice,challenging questions in all sections.

Definitely worth it to buy some CATSs over here even for a month. I would definitely recommend them.