From my observation, “hot schools” in the upper middle class context generally combine (a) predictable (or at least non-lottery level) admissions, (b) lower cost (whether it comes from merit aid or lower rack rate tuition), and (c) name brand (e.g. Power Five conference sports school and/or solid-to-great academic rankings). Bonus points are given to what’s perceived to be an attractive location (e.g. good weather, nice college town or major city). As a result, it’s not a surprise that a lot of state flagships or other top level public research universities (e.g. Pitt and Purdue technically aren’t flagships but they academically look like flagships), whether in-state or out-of-state no matter where you live, are generally hot. It’s also not a surprise that US News Top 50 schools in good locations that have a history of giving material merit aid to a fair amount of people, such as Northeastern, Tulane and Miami, are hot, too.