On several of my past visits, I've gone to UA/IOA. Universal is a pretty fun park, but IOA? Yeah, it's amazing. It is, in all honesty, the park Disney most has to worry about when it comes to competition because it -- gasp -- actually has attractions geared toward adults. While disney has focused on adding kid-friendly attractions (to the point of neutering one of my must-see attractions, Alien Encounter, by turning it into a Stitch-based ride), IOA has excelled in thrill rides.
Don't get me wrong: I love, love, love Disney. I spend a week there every year or two. Generally speaking, if I'm there during the off season, I tend to head to IOA for a day and, if the crowds are small enough, can hit all the major attractions during that day. I just wish that Disney would realize that they are in danger of falling behind in the theme-park wars if they don't step up to the plate and acknowledge that not everybody needs every ride to be kid-friendly. (Even Everest, which I love, is not what most coaster fans would call a true "thrill ride.")
If you have any questions about Universal or IOA, drop me a private message. I'll do my darndest to answer 'em!