I think Duke IM got a rep. for being malignant for a variety of reasons. The main reason is/was probably that it's one of those high powered academic places where you just work really hard, particularly as an intern, and there are a lot of patients who are...well...really sick. Also, they used to make all the interns where short white coats, like med students, and white pants; this led to the perception that interns were looked down upon, and I think they've done away with this tradition. They also used to have a generally vague reputation of not having that "nice" of an atmosphere, which I assume meant that the attendings may have been harsh or pimped a lot...again, this tends to be a true of a lot of top 20ish programs, which honestly just have higher expectations of interns and residents in terms of knowledge base, and tend to foster a more competitive atmosphere.