We flew SWA on our trip 5/8-5/14. I can't comment on the ME questions. After reading stories about the long wait for luggage delivery, we opted to do a one-day car rental to get ourselves and our luggage to WDW. We tried to use ME on the way back to MCO but they sent us to MCO in a taxi. Can't complain -- got dropped off right in front of SWA's check-in area at MCO!
I did want to comment on the lines, though. On our return trip (Saturday 5/14), we got to MCO around 4:30pm for a 6:25pm flight. The line to check in at SWA was so short and moving so quickly I barely had time to get my driver's license out of my purse before it was our turn at a podium. Lines at security weren't bad, either. It took us less than 10 minutes to get through. It seems like the day of the week and the time of day you travel makes a huge difference at both SWA checkin and the lines at security.