I say car rental--but I can only speak for car rental since I have not done ME from the airport (only to).
If you rent from any company that has a program to get you out faster (e.g.
Alamo with their kiosks,
Avis My Preferred, Dollar Express, etc) then you can get your luggage, walk across the street and get in a car and go within 10-15 minutes (just don't let the kids pick which car--it can take forever!

) Then it takes 30 minutes or so to get directly to your resort and you've got your luggage with you. I have easily gotten to WDW within 1 hr of stepping off plane.
ME--you will likely have to wait for a bus to depart and then may not go directly to your resort. Don't know if you can claim any luggage off the bus. Depending on time of day ,number of stops, etc, this can take an 60-90 minutes or more from what I have seen others post.