The question bank has reasonably good quality questions that suit candidates with quant scores above 45. Would recommend it to anyone targetting especially high scores. The verbal section is good for extra practice. Further, the analytics provided after each CAT exams are above average. I have used Manhattan, Veritas and few other tests and the analytics provided by Gmatclub stand out.
Regarding the practice questions, you can write small tests in which you can choose the topics to be covered as well as calibrate the difficulty of topics. This is helpful for candidates at different stages of their prep as they can adjust the practice questions to be more relevant for their purposes.