I think the big difference comes with the purpose of the park. . . and where there is honest value there ("heart" to "courtesy" to INTEGRITY), there is success.
Take the number one tourist destination of the world - Magic Kingdom. A place designed for the parents and the children to have fun - together! This formula worked - there is something to do for everyone. But beyond the physical rides (whether thrills or not) - and even unique theming - themselves, there is a spirit there that cannot be compared.
The magic isn't fake. The magic isn't made fun of, The magic exists in what the park is about - truly magical gatherings. And the family or friends or bonding aspect is what makes the magic real. It's not about the rides, it's not about the Animatronics - not from the root. These exterior fine arts are merely reflections of the spirit - and you're dead in the water when there is no honesty! It's about messages the park gives us, the purpose of the park as a gift of magic. . . the "Feed the Birds" philosophy. The mother and the child, the grandpa and the grandson, the friend and the friend, the honeymooners. It's for everyone, but it's also about everyone and the importance of each human on this earth to dream and keep to their "Wishes." The heart put into it, and the heart put into the guests. And that's where the 'magic' comes from in the Magic Kingdom!
Similarly, Epcot simply can't be compared to Universal because I don't see Epcot as a "theme park to be judged against other theme parks." Epcot is its own world. . . a unique and more-perfect realm that suprasses most all reality, yet celebrates that very essence.
I'm not too big of a fan of Universal, but it is its own entity. . . something I cannot compare to Disney. Kinda like AM or FM. . . TVs and Movie Theatres. All offering entertainment, but something oh so spectacular which brings Disney parks to the top, where they have been from the conception.