We love Universal and have found plenty of rides and shows for the whole family. We started going when our youngest was 18 months old and he has always loved the parks.
Having said that, our first two times in Orlando we only did the WDW parks. There were so many things to see and do and were content with the WDW parks (the first Orlando visit was when the three older kids were 4, 7, and 10, and the next (3 years later) the kids were 1. 7, 10, and 13. I can't say that my youngest, now almost 5yo, prefers WDW to Universal or visa versa. He really likes all the parks and is a theme park junky, like his mom. It's a tough addiction to break!
T&B