The brand name of an institution can only take u so far. Of course coming from a "prestigious" institution generally speaking increases the likelihood of you being a competent doctor. However, I can guarantee that you will get surprised on multiple occasions through out your career.
People from "well known" institutions will miss things that will be picked up by someone who went to "Wachupita University." This is not always the trend, but the point I am trying to make is that if you work hard and put the long hours into the system, you will become a good product without regards to the name of the institution.
I worked like an animal during my first 2 years of training which might explain partially why I did so good in my intraining tests. I don't consider my institution being prestigious at all, but I played hard and got rock solid #'s to prove my knowledge base.