Hi, I took the Kaplan course (classroom, two months) and I think it was worth the investment. It definitely provides you with tips and strategies for the GMAT. But, if you need a review of basic maths, I would suggest taking a separate course as a general refresher. Thus, if you are good at maths, then you don't need a math review (obviously!), you can just take the Kaplan course to get good tips. I think they also have a weekend crash course if you really don't want to spend a lot of money (it is expensive!). Hope this helps.