There's an interesting graphic at the below website for wait times at US airports, displaying percentage of waits over 10 minutes, average wait, and maximum waiting time. You can click on each airport and see the breakdown by checkpoints within that airport. The airports are ranked by domestic passengers whose trips originated at that airport and not including aircraft with less than 60 seats.
The figures were compiled from June 1, 2004 thru May 16, 2005 by the TSA.
Locally, the figures confirm that FLL (ranked #13 in domestic pax traffic) had shorter wait times than MIA (ranked #34 in domestic pax traffic). Of course, like gas mileage, your wait times will vary according to when you fly. Here's the results:
FLL - Waits over 10 mins 12.7%, avg wait 4.8, max wait 100 mins
MIA - Waits over 10 mins 14.2%, avg wait 5.6, max wait 101 mins
Concourse B at FLL (serving Southwest, America West, Frontier, and others) was second lowest in wait times at FLL with only 8.9% waits over 10 minutes, an average wait of 4.5 minutes, and max wait time of 48 minutes.