I don’t know the criteria for “hot” either, but anecdotally from here in North Carolina, for OOS students, Elon and High Point U are the ones I hear about. These are not very popular with in-state students, though. They seem to draw mainly from the Northeast. For my money, as a NC parent, I would not send my kid to one of those because there are much less expensive and better in-state public UNC-system schools. They are kind of head-scratcher for me, but OOS folks seem to like them.
Of the in-state publics, I would say Appalachian State and UNC-Charlotte are getting the most momentum. UNC-Chapel Hill and NC State have always been very popular and selective in-state options.
I think East Carolina is getting some OOS interest too, and they have expanded a good bit in the past decades and offer a wide range of highly regarded health-care oriented studies. ECU does tend to serve students from the eastern part of the state who want to stay closer to home, but kids from all over go there.
Here in the middle of the state, though, I hear more about UNC-Charlotte and App (and UNC and NC State, but those are pretty hard to get into). My kids go/went to a NC charter school and about half the class of 2019 went to App State. UNC-Charlotte has been growing like crazy lately and transforming itself from a small commuter school to a major state school. I think the enrollment has grown by 33% over the past 10 yrs. UNC-Charlotte has passed UNC-Chapel Hill (the flagship) for undergrad enrollment at somewhere around 22,000 (overall enrollment almost 30,000). UNC-Chapel Hill has a larger overall enrollment because of graduate programs, though.
UNC-Wilmington is also fairly popular, but it’s more of a mid-size campus (15000) enrollment.
Western Carolina (WCU) is also gaining some momentum due to the crazy cheap tuition deal the state is offering there now ($500 in-state, $2500 OOS). The state also has the same deal for Elizabeth City State and UNC-Pembroke, but I don’t hear as much about them. WCU is in a much more scenic location.
Davidson and Duke are always popular and super selective and super expensive.