First off, as already mentioned, whether a course is helpful or not is personal preference.
Although you mention a course is "obviously beneficial," this really isn't the case. There are many times when a course is no better than simply studying by yourself. The main positive of a course is typically the amount of practice material. Yet, there are many ways to get enough practice material without coming close to the cost of a course. I will say this, if I could redo the months I spent studying for the MCAT, it would NOT include a course.