Not sure about Orlando but recently rented out of Tampa...
The lines at the main counter were pretty long. I had Preferred so went down to the garage... there were 5 or 6 people in front of me and two working the counter. Took about 15-20 minutes or so.
Fast forward to drop off... due to airline problems we had to go to Jacksonville airport. When walking though the terminal the line for
Avis looked pretty substantial although the preferred counter only seemed to have one customer.