I was looking for a course that could help me structure my approach towards verbal, especially sentence correction. After going through one of the blogs by E-GMAT on the gmatclub forum( I think it was on modifiers), I felt that it was exactly what I was looking for, a well organized and step-by-step approach to sentence correction which appealed to my mathematical mind ( Yes. I am an Indian Engineer).
The course covers all the basic concepts and helps to build a strong methodology which can help you shorten the time spent/question and improve accuracy.
You also get multiple tests on two different portals(25Q and 9V on GMATclub and 5 complete tests on 800score), which helps you gauge your progress more accurately.
Thanks to the course I improved my score from 710(Q50 V34) to 750(Q51 V40)
PS- There are not many sample questions.So keep practicing on GMATclub forums there is sufficient material available here. The best approach would be to strengthen theory on E-GMAT and put it to test on gmatclub.