I get kind of confused when I hear people say that Universal Studios quality is not even close to WDW. I am as big a fan of Disney as anyone but I also enjoy a day trip to US.
I think that the attractions are very well done and themed in the same manner as Disney. In some cases, (sorry about this) I even think they are better. When your number 2 you try harder. Terminator, Back to the Future, Earthquake, Tornado are "not to be missed" attractions. Men in Black, Wild West Show and others are really good as well. In short, it is well worth a look see.
The only word of warning is that, it has always seemed to me that the lines are longer and a little more "hidden" than Disney. It can be discouraging to think you are almost at the beginning of the line only to turn the corner and find the population of New York City winding it's way behind an unseen barrier. Other than that, I think it is very well done.
I have not been to IOA because I am not a thrill ride seeker, but others tell me it is done pretty well also. When time allows, I almost always take a day trip to Universal.