I think the problem you are running into, and Joe and the other poster mentioned, is that there is NO roadmap to success in medicine or business. There are key traits such as drive, intelligence, and social skills. However, every question you asked has no wrong or right answer -- If someone tells you taking this degree or whatnot it would not mean you are more successful.
Successful people do not have degrees or tests they've taken in common, they tend to have the same character traits though.