I've used DME about 4 times now, and have had only good experiences to date. I have flown into Sanford in the past...nifty little airport, very user friendly. But, it is almost twice as far from WDW as MCO is...takes about 50 minutes to get to WDW. I would only fly into Sanford if I got a really great airfare, in order to make up for the cost of a car service picking me up.
If you get decent airfare into MCO, I would heartily recommend DME...it takes, on average, about 65-70 minutes from deplaning to your resort. Your bags will arrive at your resort several hours later, depending on time of day.