I have some familiarity with these programs.
WF:
My knowledge of this program is really only by word of mouth. Supposedly a very nice hospital. Lots of ancillary care, step-down unit, etc. Has patient base from western NC. Did not apply or interview here, however.
UNC:
Covers NC Memorial (on UNC campus) and Wake Med. When I interviewed, I felt that UNC is a very warm-fuzzy program. Program's philosophy is to learn IM by first mastering core-IM. Fewer specialty-oriented rotations, especially during intern year. Fellowship match list is still good, however. Benefits from having Med-Peds program; morning report is certainly enriched from having these residents. IMO, UNC is overall a very solid program on par with Vandy, UAB, UVA, Baylor-level programs in the south.
Duke:
Covers Duke, VA (across the street from Duke), and Durham Regional (15 min drive). The bulk of the 3 years is done at Duke or VA, so residents will not need to drive as much as you would think. Durham Regional also has its own morning reports, and noon conferences are held in conjunction with Duke through telecommunication (again, very little need to drive between the two sites). Currently participating in the EIP program, where you have concentrated ambulatory blocks, but very rarely would you have continuity clinics during inpatient blocks. There is overall less continuity on the outpatient side, and more team coherence on the inpatient side. Lunch provided on all weekdays, and dinner provided on call nights (even on weekends). Interns and residents come from all over, from Penn/Hopkins-level schools to less-renowned med schools... but nearly all are very accomplished. Has med-peds and med-psych; again morning report is enriched by having these residents. Overall has a robust international as well as national/regional reputation. Speaking of international reputation, Duke has a good number of established oversea rotations for those interested in international medicine.
Fellowship matchlist is very good, and there is strong advising/support within the program to help residents match into desired fellowships. Many of the IM fellowships are very strong at Duke, including card, GI, heme/onc, pulm, renal, geriatrics, and ID. A bit less prominent in endo, rheum, and CC, though by no means weak or even average.