The one and only time I used ME it took us two hours from MCO to Boardwalk. We were on a late flight from NYC area, didn't have any checked luggage. We figured it would be quick, since it was so late (we landed around 11p) but nope.
We made it to the bus, waited a bit for one to come in, got on with another two families. Waited there for at least 20 minutes (my guess is that they were waiting for another family that was suppose to come in but never showed up)... then off to first stop Art of Animation to unload one family waited for them to get their luggage from under the bus, moved onto our next stop one of the All Star resorts again waited for that family to get off and get luggage, then finally off to Boardwalk.
Ended up canceling our return trip calling up our usual car service since we didn't want to waste the 3 hours (we usually use a car service but figured since it was late and would't be too crowded, we would save some money... just not our cup of tea)