I've been an AA flyer since 1989 and EXP for the past 10 years, and I'm married to a woman from (and who's parents still live in) Miami, so I have a lot of MIA experience. And while I can remember some long lines for security, particularly in the post-9/11, pre-TSA precheck, days, and I recall one painfully long wait for checked luggage years ago, I can't recall a single experience that would make me recommend that MIA be avoided like the plague. Yes, it's a busy airport. Yes there are a lot of people who <gasp> speak a foreign tongue. But it generally works fine.