Even when I use a towncar service, I still ask them to pick me up 2.5 hrs prior to flight time. I want to be at MCO 2 hrs before my flight. I would much rather spend an addtl 30-45 mins at the gate vs rushing and worrying about not getting there in time. And, I've arrived 90 mins prior to departure, and that's when security was backed up, there was only one tram running..it was nuts!!!
Up to each person to decide what works best for them. If you really want that addtl 45 mins of sleep, then sure....have a car service pick you up at 5am. BUT...don't be lulled into thinking that the airport will be not so busy early in the morning. You will have lots of company!!!
Then again, this is why I don't book flights prior to 10am!!! Way too lazy to get up and out before 7am!!! And I want to use RAC to move my bags!!