We (kids were 6 and 10 or so) did two trips to Universal, 5 days and 4 and we were able to fill them up really well with the two parks and the water park (spent 8AM-8PM there). However, others are content with 1-3 days. We really enjoyed several of the themed areas. It doesn't have as many shows as Disney (or as many as Disney used to have), but they have some and the rides are good. A lot of it is that the lines are so much shorter (especially if you have express pass) that you get so much more done quickly.Oh, so Universal isn't a week or even a two week thing? We have gone to disney for anywhere between 5-10 days, with the 10 days option being our favorite trips....
We had two trips to Disney and while we had a wonderful time, the kids have no real interest in going back.
Joseph