I have no major issues when travelling domestic through MIA. International is another story. I really stay away from International as much as possible. The set up of one central Imigration office is a huge drawback. I can talk of extreamly long queues to get through and a fist fight between 2 people my last time. I had 2.5 hours connection and almost miss my connecting flight. I am glad that the pilot of my connecting flight was late due to traffic around the airport.

It is a long long walk due to their set up between entrance and gate, but it is worse when you have to deal with long queues and agressive staff.