humbled4real
At the end of the day, what do you call the person who graduated last in his class from medical school? I shrugged and he simply said "Doctor". Then he said, when was last time you went to a doctor and asked him where he obtained his degree and license to practice medicine? Never! And you trust that person with your health. . .
My point is make the decision that is best for you. Don't worry about what others experience has been because all you can make or break your path. Good Luck!!!
Thing is, medicine and business are fundamentally different. Once you've gotten into any medical school (when I applied many moons ago, only 33% of all med school applicants were getting in anywhere... I don't know current numbers), you're effectively "in the club." Certainly an MD from HMS or Johns Hopkins will help you get where you want. But I know people from much lower-ranked schools who've gone on to great training programs and have become leaders in their fields. Conversely, I know folks from top-5 schools who failed to match into any residency program and had to scramble for training positions. It's a relatively egalitarian sort of thing dependent on grades and evaluations, dean's letters, USMLE scores, etc.
Business is a bit different. Once you start working at a company, your progress certainly depends upon your accomplishments. No argument there. But how do you get that job in the first place? HBS, Stanford, Wharton and others will open doors that would otherwise be unreachable. Later in your career, when you decide you want to move to another company or position, a school with a strong and accomplished alumni network will help you make that transition. The alumni network doesn't really exist in medicine. If you want to join a high-profile academic practice or successful private practice, they look at your CV and take a look at your training program(s), publications, and number of procedures performed (if applicable). If you attended a top med school and did well, that's nice but it doesn't end up carrying a lot of weight. The med school, in the end, serves as a stepping stone to your residency. And that's pretty much about it.
Edit: Sorry, that turned into a little diatribe. My point in the end is to get into the best business school you can. As humbled4real points out, once you get to school you do set your own path.