No charge...at least that you can actually see. The cost for DME is included in room rates. So, basically, everyone is paying for it in their room rate.
I have used the 'old' Mears shuttle, DME, a car service (with and without checked bags) as well as the newer Mears shuttle. Here are my times....sort of, as best I can remember them.
DME...average of about 70 mins from gate to resort. Some times have been just under an hour and one was close to 90 mins..most right around 65-70 mins.
Car service....carryon only...gate to resort was about 45 mins. With checked luggage it was about an hour. ($125 plus tip)
Mears shuttle..to S/D, carryon only....75 mins. ($19 one way).
It all depends on the type of experience you want. And what you are willing to pay.