MIA is a horrible airport to fly to and from. Parking is $8 in the park and ride and $15 per day in the garages, which is pretty pricey. We reserved parking online at a nearby independent lot with airportparkingreservations.com, which was helpful.
Right now, MIA has a lot of construction going on around it, which makes driving there not very much fun. The airport itself is pretty confusing and disorganized, but it has quite a few shops and restaurants before you go through security. After you do go through there isn't much at all, so make sure to get a nice cuban coffee before you go through.
MIA is also quite crowded, and there were huge crowds at baggage claim. Luckily, the baggage claim conveyor belts did have digital signs above them saying which flights were coming out on that belt because our pilot told us the wrong belt when we got off our plane.
The plus side is that it didn't take long to go through security. I'd rather fly out of FLL or PBI anyday, PBI is my favorite airport.