I have been using gmat club tests since past 2 months, and I must stress there are no tests out in the market that come close to gmat club tests in terms of quality of material, especially for quant. I personally feel that gmat club quant tests are better than Manhattan Cat tests quant. For verbal I would say gmat club team still needs to improve the content to come at par with other prep companies. For someone aiming for a Q 50 gmat club tests are a must and more than enough. The kind of flexibility gmat club tests provide in terms of taking tests or quizzes and the large collection of questions help one achieve more fruitful outcome.