I have not been to Universal. I have, however, researched the park and spoken at length with people who have gone there numerous times. Fundamentally, I couldn't find any compelling reasons to spend the time and money allotted on a park themed after things I really don't care that much about. The heavy focus placed on the Harry Potter films is a particular non-starter for me (thought the first movie was tedious, skipped the rest along with the books). I feel my decision is a considered one, subject to change if conditions warrant. While I'm sure Universal is an entertaining park, it currently offers little entertainment value to me.
Sometimes we don't know what we are interested in until we actually experience it. That is my reason for diversity in my Theme Park participations. Nothing, but, unthemed roller coasters will not bring me to any park. Quality will!