IMO the event was more intense at IOA. Back then the scare zones were just over the top and worked so well within their environments. I also think the creators of HHN were being a little bit more creative back then with concepts, house locations, and offerings. Not saying everything always worked because I assure they didn't. Many people will tell you they hated the IOA years due to the crowds and lack of appropriate haunt venues. i mean some of the worst houses ever came from those years. But in the end IMO the event just seemed to be so well tied together at IOA and offered non stop scares all the way around the park, except in Suess.
This. I remember literally fearing for my life as a little kid in Island Under Siege and the Terror Mines. The streets were more energized and such and it just felt better at IOA. I just don't feel the higher scare factor at USF. Partially because I'm older and harder to scare, but its just not as scary as it was in IOA. The closest I've gotten to that lately is HHN 21. I will vouch for the crowds and waits stinking massively, but the themes, icons, and overall streets flowed much better at the other park. Also, Body Collectors, All Nite Die-In, and Screamhouse? Enough said.