It's also setting dependent. I interviewed in 24 different states for residency, quite a few East coast and also a good swath of the middle of the country. I can tell you right now there was no where East of the West Coast that I thought a man bun would receive a consistent neutral reaction. So many more places I had the vibe the man-bun was not going to fly, and keep in mind at the residency stage as an applicant you have a little more... I don't want to say power but the word escapes me.
I also find that not only was the culture where I went to school and trained... more "hippie," but even that said, I think I've found that as a function of not only my age, but also being on SDN, that I likely have come to project a more "accepting" attitude onto the health care field than actually exists. Meaning, not sure that my viewpoint is representative of the physician brotherhood.
So even where I was, and now as part of the admissions process, I'm not sure that even where I think it might be OK, that it really might be OK. I think I underestimate the conservativeness. And I think that says something when I'm the young otherwise open-minded doc shaking my head at bad shoes. Sure, I forgive a man bun especially if the applicant seems on point. I'd like to believe that's a truism where I am, but not sure. And where I am, where bilateral full sleeve tattoos and gauged ears don't make any of the faculty bat an eyelash at the med students who sport them, and here I am, I'm not sure how the man bun is really OK, well, that's really making me pause and wonder if it's OK anywhere. If I hesitate to say it's OK in hippieland where almost anything goes, then I can't say it's a good idea anywhere.
I say it's too big a risk for the man-bun for med school interviews. If you're going to do a man bun, don't do it until you have an admission. That's the biggest hurdle. You will probably graduate and match somehow somewhere all while sporting your man-bun. But that's only if you pass go.