The area around MIA is not the classiest... Okay, aside from South Beach, there's not MUCH classy about Miami. (Can you tell I'm not a fan? I live on the Gulf Coast. Miami is like another country to many of us.)
The MIA Hotel is attached to the Airport (obviously). Never stayed there, but it looks okay from what I've seen of the lobby area. A good alternative is the Wyndham Airport (also on the airport property). There are also a couple hotels across the highway to the south, facing the runways. One of them is a budget all-suite hotel that I've stayed at a couple times (not sure of the name any more, as it's changed a time or two). It's in a business area, so much better area than many of the other hotels.
Another option to look at, if you have the time, is to get a hotel in the Coral Gables area. Hyatt, Sheraton, etc., are down there, and rates are reasonable. The Miracle Mile is a great place to walk around and soak up the local atmosphere. And if you're looking for good restaurants, that's the place to be. (Drive to the airport from there is also not too far; 15-30 min at the most.)
Best of luck to you, and enjoy Miami (as much as you can)!
