To tell you the truth, I am the biggest fan of Walt Disney World and have no desire to ever visit the Universal Studios theme parks because they in no way compare with the Walt Disney World theme parks, but in your case I would spend the two days at the two Universal Studios theme parks. Walt Disney World has four theme parks, two water parks, Downtown Disney, and a great selection of recreation, so it would take much longer than two days to do everything they have to offer. In fact, you'd need at least a week to really, fully enjoy Walt Disney World. If you were to go to Walt Disney World for those two days I'm sure you'd really regret that you couldn't stay longer. It's really not worth it if you can't experience it all at once because once you realize how amazing it is there you'll feel awful that you couldn't stay and do everything. You'd be much better off saving the money for a longer trip to Walt Disney World in the future. See, the Universal Studios theme parks are not anywhere near as large as the Walt Disney World theme parks, so you can easily do everything there in two days. You actually may have time left over. There's really not too much to do at the Universal Studios theme parks. They're only popular for their small selection of roller coasters. For every one attraction Universal Studios has, Walt Disney World has ten. Most people can do everything in both of the parks (Universal Studios and the Islands of Adventure) in one day.
Anyway, hope I could help and I hope you and your husband has a wonderful birthday!
* Shiomi Ryuu - Walt Disney World was not created for children. It was created for families. It was created for adults just as much as it was created for children, if not more. Children can't go to Walt Disney World without their parents bringing them, so Walt Disney World needs to be able to draw in the adults more. There's so many things for adults to do there. I go with my boyfriend every summer, just the two of us, and we always have the most romantic time. And we never stay for less than a week. We do not have children, aren't necessarily fans of Disney movies, and we still have the most incredible time of our lives. Pleasure Island, the ESPN Club, the Atlantic Dance Hall, Jellyrolls, the Big River Grille & Brewing Works, all those alcohol stands around EPCOT... yeah, I highly doubt that's meant for the kids. Walt Disney World is definitely better than Universal Studios, whether you're a child or an adult. And that's not just an opinion, that's a statistic. In 2005, Universal Studios' theme park's annual attendances decreased by 8.5 percent while Walt Disney World's theme park's annual attendances continued to climb by at least five percent. Also, Walt Disney World is the number one vacation destination in the world.
* Jessica - "MGM" (the Disney-MGM Studios) is one of the Walt Disney World theme parks. Universal Studios is one film making company and MGM is a completely different one. Universal does only have two theme parks at the Resort in Florida.
I am a Walt Disney World Expert and also have much knowledge on the other theme parks and the Orlando area.