My husband and I had to rent a car during our annual trip to Miami for Christmas and I almost fainted when I saw the prices of the major renters. I saw a mention of ACO here and decided to go with them because their price was about half of the others.
I was a bit apprehensive because they are not located in the main Rental Car Center but was pleasantly surprised. They have a shuttle that takes you from the RCC to their car lot. The agent upgraded us from a Corolla to a Camry free of charge, and had us on our way quickly. We returned the car to their lot a week later and were taken directly to our terminal for our flight. Overall I was very pleased with their service, quality, and especially the price.
While it may be a slightly more convenient to get a car right at the Rental Car Center at MIA, I thought it was well worth the extra 10 minutes it took to save about $400.