we used ME while traveling on SW in May.
I don't think they let you get your own bags when you arrive at MCO. They don't load the bags on the bus that you are traveling on... it goes separately. However, we loved it for the trip TO the resort. It was nice not having to deal with the bags. The bus was quick to leave for the resort...we checked in to the room, changed (had stuff in a carry on), and were off to the parks. When we returned later that night, the bags were waiting in the room.
However, I think if I were to do it again, I'd take a town car for the return trip to the airport. Stopping at the other resorts when trying to get to the airport on time was a little much when you are concerned about flights. Also, they drop you at the lower level where the ground transportation is. For us to get to SW ticketing, we had to go inside, up the the main floor, and then trek pretty much to the other side of the terminal. The town cars drop you right at curbside check in. Given the long lines at SW check in, I think that works better.