I have had a lot of towncar drivers try to tell me that if they pick us up 90 mins prior to departure, we'll be fine. Ah, no. There is a reason MCO recommends getting to the airport 2 hrs prior to flight time. So, when I use a car service, I always have them show up 2.5 hrs prior to departure. Security at MCO can be really nasty...and you don't want to be standing in that line, stressing over the fact that your flight is going to start boarding in 30 mins.
I realize that being picked up 3 hrs before your flight seems excessive. But, it really isn't. You save maybe 30-45 mins using a car service....or better said, going back to MCO in some way other than DME. It's up to each person to decide what works best for them, and their family. I just like everyone to have the correct info in order to make a well thought out decision.