GMAT club test helped me improve my score on day to day basis. Unlike other test series where we have to complete both verbal and quants in a single go. Here we have both of them separated. In this way we could practice Verbal and quants on alternative days.
Verbal mock scores were very close to actual ones, but quants used to be on tougher side. I got my verbal improved from 25 to 35. They have huge set of question bank.
The only drawback which I found here is that, we don't have adaptive tests. You might have solved a 700 level question, but then the next question might be a 600 level questions.