One word....Monorail. At WDW this means either the GF or Poly (for us) and at DL it's really a wash, as the GC dumps directly into DCA and the monorail drops direcly into Tomorrowland. No transportation issues, no shuttles, driving or parking - just roll out of bed, grab a coffee, shower and pass and hit the parks
Then there's the total emersion Disney thing, all the small things in the rooms etc. We stayed off property once - never again. They even pipe the music for the fireworks into the concierge lounge at the Poly and into Narcoossee's if you happend to be there at show time.