We stayed at the Residence Inn Miami Airport West / Doral. It was completely fine, but certainly not a vacation destination, more of a "clean place to sleep so you don't have to board the ship on travel day."
Transportation and rental car options to the port are tough in Miami if you have kids that need a car seat. We had no choice but to rent a car to get to the hotel, return the car to the airport the next morning, and take Disney's shuttle to the port.