The beds there are SOOOOOOOOOOOOOOO comfy. The express pass, especially with the kids. Our APs cost us $270 a piece I think. Overall, he enjoys the theming more with movies and cartoon characters/comic books over Princesses. Oh, and the boat to the parks. Convenience, price, location....and pool hopping.
I love it too, I just LOVE my Disney more

Plus, IMO US/IoA can be done in 2 days...WDW cannot. But the Universal resorts also have a slight edge on activities. Pool games, kids clubs when it rains...my girls loved the free frozen grapes they bring around at the pool.