The instructor seemed very good. But it seemed that the material they would cover in the course would only be the easy-moderate level (this was clear from the level of students in the course, i.e. one guy in my class didn't know what a prime number was or could he give an example of one). If you are really trying to nail the GMAT (and you think that you can), I doubt you really need a review of the lower-mid level material. You should focus on the difficult concepts. From the MGMAT course, I didn't see a lot of the instruction centered around this. Hence, you would be on your own to study the difficult stuff anyway. With the course you would have the instructor as a resource though (although I think the forums are just as good). They do offer other perks, like practice test review and feedback. And like I said, I think the books are a big bonus. Oh yeah, one more thing, they mainly review and teach with the questions in the OG11. And you can usually find good explanations in the book. In fact all of their study guide books give good background, then refer to OG11 for problems. MGMAT SC is the best for concepts though.