We have been to Disney a few times, but this past December we went to Universal & IOA for the first time. We ended liking Universal better than Disney. It was me (39), Dh (37), dd1 (19), dd2 (12), and ds (7). I don't ride much, but dh & the girls really enjoyed the thrill rides. Ds wasn't tall enough for the bigger stuff, but he still had a great time.
We spent two days at the parks, but we didn't get to do everything. We probably would have, except dd1 was in the Macy's Parade (that took up a good chunk of time).
We are already planning our next trip (for this December), and we plan on spending one day at Disney and a few at Universal. My biggest suggestion is to stay onsite for the FOTL access.