As an OOS parent, Miami is appealing as a small, private school for a lot of reasons. It isn't something that is widely publicized but Miami gives A LOT of scholarship money to incoming freshmen (and renewable through 4 years) and OOS students are as eligible to receive it as in state Florida residents. These scholarships range from a few thousand dollars to full tuition for 4 years. Much of this scholarship money is based purely on test scores - SAT or ACT. In addition, there are many, many, many scholarships available to Florida residents, students of various minority groups or those with other special circumstances. This kind of financial support is huge given the very high tuition. In my experience over the years, there are few other schools- especially private schools - that offer OOS kids the same kind of scholarship opportunities. These are NOT loans; this is outright scholarship $$.
My kids have many friends at Miami from Florida. They have always said the order of preference for kids who are concerned with academics is Miami, UF and then FSU. If financials become an issue, kids accepted at both Miami and UF probably end up at UF due to cost of attendance.
And btw, there is no guarantee siblings are accepted at UM, regardless of whether they are Florida residents or not...