what a lot of former residents/current attendings have told me is to read medstudy for content, and to do mksap for questions. seems like the majority of people say that the questions on mksap are much harder than the actual board exam. as i'm in the same boat as you, i don't know that to be a truth, but have certainly heard it time and time again.
rather than physically go to a course, i actually ordered the dvd's for the acp course, and looked at a few of the med study course dvd's as well. schedule-wise, dvd's were a better fit for me than going to a course.