We used Hertz @ MCO for the 1st time last month w/ a Priceline rental. The shuttle took about 2-3 mins to arrive, we got on and then waited another 4-5 mins before we finally just asked if we could leave. There was another bus behind ours so I'm unsure why we waited.
We aren't Gold members so we were unable to be dropped off at the car, went inside and there were about 8 groups in line in front of us, this was about 10:30 am on a Fri. Waited about 15 mins before I got to the counter and it only took a couple of mins to get the keys, but before hand I asked if the car was non-smoking and they said it was. Walked all the way out to it to find that it reeked of smoke. Walked all the way back to the counter, and tried to wait off to the side, but a different agent was telling me to get back in line.
I explained the situation and then waited about 5 mins for an agent to get free and arrange for a different vehicle. We ended up in a 2007 Toyota that had about 200 miles on it and was designated as a non-smoking car. No problems with it, returned it easily and waited on the shuttle about 3-4 mins before leaving for the airport.
I didn't love my experience with Hertz, didn't hate it. For future trips I'm going to book with an on-airport rental agency, just my .02!