I don't know how long the security lines are at MCO are now, but on Dec. 30 it took us 40 minutes to get through security. This was for a noon flight. Others can tell you how long the wait is now.
We have taken towncars at least 25 times from MCO to WDW. After waiting for our baggage and then waiting for the towncar driver to come around to pick us up, I found our two recent experiences with DME to be as fast. On Nov. 29 we were checking into the WL in a little less than one hour after we departed the plane. We stopped at the Poly then on to the WL. On Dec. 25 we stayed at the YC and were checking into the YC 1 hour and 15 minutes after we left the plane. We had two very good experiences with DME and others will tell you their bad experiences.
They did pick us up 3 hours before the plane departure time and were prompt. We did have extra time at the airport on Dec. 6, but with the long security lines on Dec. 30 our extra time was minimal.
I can tell bad stories about the towncars also. Once they never picked us up for our trip back to MCO from the GF. After many phone calls we gave up and the GF furnished us a ride to MCO at no charge. We barely made our flight. This was a company called Florida Towncars. Two times Tiffany TC didn't show-up for the trip to MCO, after calling them they did show-up and again we barely made it to the airport in time. If I recall the towncar companies picked us up about 2 hours before our flight departed. If you don't like the 2 hour schedule you can tell them either earlier or later.
I think you should do what you feel comfortable with, because you will get all kinds of different experiences from the people on this board.