OK, I just made it through all 19 pages of this thread. I officially have no life
I want to throw my two cents into the ring. Background -- I'm in my early 30s now. I was raised 45 minutes from Disney with an annual pass. I was 14 when Universal opened, so that may color my feelings a bit.
I like Disney, always have. At one time, I loved Disney. When Universal opened though, I felt like I finally had a choice. BGT, SW, even the old Circus World... enjoyed them all, but never felt like they could really compete with Disney.
For me, Universal opened up a whole new world. I think the parks are every bit as immersive, well-themed and full of magic (yes I said it) as Disney. But they're not sanitized -- nothing to do with cleanliness, US is always pristine when I'm there. Universal is edgier, they push the envelope further. I love that. I enjoy going to a beautiful, clean, immersive, well-themed theme park that doesn't insult my intelligence or shy away from anything slightly PG rated.
My first job was at Universal, on Kongfrontation. Over the years I have worked attractions at both Universal parks and two Disney parks. I also did food service at another Disney park and worked as a scare actor for
HHN at Universal. I have to

at the people who say that CMs are "nicer" or "more helpful" or "friendlier" than TMs...I don't remember having a personality transplant when I changed costumes
I also get really confused when people mention Universal's "lack of theming." Um, you are aware that the vast majority of Universal Creative team members are/were Disney Imagineers, right? Matter of fact, Bob Gurr, who has done a great deal of Creative design for Universal, was inducted as a Disney Legend in 2004. He started with Disney in 1954 under Walt himself! Tell him how lacking the Universal parks are...
Another example, though it's no longer as relevant since Harry Potter's taking over part of Lost Continent. Do you know the backstory to Lost Continent at IOA? It was supposed to be Beastly Kingdom at AK! Disney nixed the budget, and the Imagineers who had been working and planning for years didn't want to lose their work. So they took it to Universal. Some things were obviously changed, but the framework was designed for Disney, and Universal was smart enough to take advantage of Disney's poor management decision.
Somebody a few pages back mentioned that Disney feels like "home." To me, Universal feels that way. Working for both parks may have colored my feelings... the truth is, Disney treats its CMs like dirt, with awful pay, crazy schedules and few perks. Universal pays (a little) better, is much more accommodating of schedules and does a ton of extra little things for its team members. Universal also has way better discounts for employees.
Or maybe it's my AP status at both parks. What do I get at Disney? A small percentage off the sky high room rates and cheap mini-golf? At Universal I also get discounts at every restaurant and merchandise location, passholder parties, a hugely discounted Frequent Fear Pass for HHN, the list goes on and on.
Universal also listens to guests. They have a much more extensive polling system than Disney, constantly stopping park guests to ask their opinions of everything from shows to rides to food service. Once you've done a survey, you can sign up to do additional online surveys as well as in-park focus groups. Then they act immediately on feedback. For example, I took a survey on the Freddy Krueger haunted house at HHN last year. I said the house was great, but there were too many Freddys and not enough victims. Apparently I wasn't the only one, because the very next weekend there were twice as many victims and half as many Freddys. That's just one small example of how well Universal is tuned in to guest preferences.
I don't hate Disney. As I said, I really like it. But as costs continue to go up while quality and service go down, I'm starting to wonder whether to renew my AP. At Universal, quality and service just keep getting better and better, while prices remain low.
For me, Universal is home. Universal holds the magic. Disney has lost that title.