While there are benefits to this method, because hierarchical systems usually require formality and support a culture of supposedly "masculine characteristics" (e.g. your boss should be tough, commanding, and authoritative -"masculine characteristics" vs. your boss being nurturing, listening, and understanding -"feminine characteristics."), students get stress from students. Specifically, I get criticism from a friend, a student, but ultimately my boss.
I cannot deny that the ability to take feedback well is a fantastic characteristic to develop. It is especially crucial if you work in any manner as a team. I want to point out that this isn't being silent as someone gives you flack. Being able to see your mistakes is step one and taking steps to not repeat them is step two, and having someone point these out is feedback. (I believe the politically correct term is "constructive criticism.") In fact, being able to give and take criticism is a sign of a healthy, professional relationship.
However, because the boss-worker relationship is formal and not many college relationships are formal, having your friend be your boss is difficult in any situation. I hope I remember this when I am on the other end.