Samesies. When we visited last September I understood why Universal Studios closed early, it was an HHN night, but IOA was only open until 8pm that night, as well. Like, holy hell, if you're gonna boot everyone out of one park, at least keep the other park open to a decent time. We only had one day to do both parks. Thankfully since it was such a slow week we were able to bang out every single attraction, even the horrible ones (F&F&F: Fast & Furious & Fallon), but it would have been lovely to have the extra evening time to enjoy IOA's atmosphere and a few more rides rather than going back to our hotel and being bored.
Dinner at Antojito's was friggin great, though. They put us right next to the stage and the evening guitarist was wonderful.
Edit - Just for comparison's sake, the next day we were at EPCOT by 9:30am and didn't get back to our hotel until nearly midnight. Park closed at 10, we took our time after the fireworks to walk from the Japan pavilion, browsed the gift shop, and were among the last few groups walking out of the park, never once feeling pressured to GTFO. Universal felt like they were actively pushing us out of the park the instant the HHN corrals began around 3pm and IOA had a ton of disinterested employees that were happier to talk amongst themselves than engage with the park guests. It felt very Six Flags in terms of service.