Aventura has an extra-demanding clientele because it's mostly Central/South Americans who patronize the store. To afford Apple products in many of those countries, you're upper class. Full stop.
Apple is a middle-upper level luxury brand in America, like Lexus or BMW for cars. To south/Central Americans, it's more like Ferrari or Rolls. When they shop they expect and demand the highest level of service and treatment, and I can say the local Apple stores do a very good job handling it. This ain't Minnesota-nice around here, customers from abroad are tough and expect excellence, to say nothing of the invariable language barriers. Any South Floridian who has worked retail knows all too well that when you're handling three customers at once, and one speaks Russian, another Spanish and the third Portuguese... You're earning your money.
Have you seen when "they" come in with suitcases and fill them up with Apple products to go back home and sell for mega profit?
Ya, this Apple Store is the highest trafficked store in the Mall, and I would say, all of South Florida. And just by frequenting this store about once a week, my guess would be the mix is 75% non-US citizen and 25% US citizen.