Well we don't have to take the shelf for med-micro, so I might not be the best person to ask but since no one else is contributing, I will say that I have taken 2 shelf exams (Anatomy and Biochemistry) and did very well in both using the BRS in those subjects as my principle resource. I know this isn't much help but if I did have to take the shelf in med-micro I would use the BRS. Good luck!