My husband who never, ever gets sick on any ride, got very ill after riding FJ and in fact felt off the rest of the day. He can ride Star Tours over and over with no problem. He decided his system was just off the first time he rode FJ, so tried it again the next trip. I gave him a Meclizine the night before and another that morning to make sure he didn't get sick. He argued with me that he didn't need it and would be fine.

Nope, still felt ill after getting off FJ. It wasn't as bad as it was the trip before, but still made him feel off. He sat outside while I rode it over and over using the single rider line.

I love it and have ridden it over and over many times, jumping off and getting right back on through the single rider line.
He loves motion simulators, roller coasters, even the tea cups don't bother him, but for some reason FJ throws him for a loop. After taking Meclizine he will ride it once now, but that's it for the day. He's still not fond of it. Going through the fireplaces at the beginning of the ride and when the bench dips right after Hagrid asks if you've seen the dragon are the main parts that affect him.