I did KI Haunt in 2023 and Six Flags Great America (Illinois) FrightFest in 2024.
KI, as you know, has had the mazes included with admission. There’s an upcharge for FrightLane which allows you to join the shorter line once per maze. My experience in the houses especially were a little lackluster, as folks here have shared regarding theirs.
The FrightFest event you could be in the park on a regular ticket or pass. This included active and fully staffed scare zones. The mazes were $40 for a night and $80 if you wanted an express line. Both maze passes were unlimited. We did Texas Chainsaw Massacre 3 times. Three of the five houses were popular IP, like Texas Chainsaw, Stranger Things, and Saw. In addition to the upcharge for houses, during the day they had Octoberfest area setup with punchcards for food and specialty drinks.
The FrightFest mazes and scare zones were done much better. I’d compare it to WinterFest at KI where your pass can get you into the park, but they also have a lot of upcharge items (ice skating, cookies, specialty food, etc.) which allows them to do the event.