My hubby will NOT do spinning rides, like the tilt a whirl or the tea cups but he has never passed up an opportunity to do MIB and will ride it multiple times in a day...no problem.
My now-9yo had a major vertigo issue when he was little that caused him to fear anything spinning but he loved MIB and didn't have a problem.
He didn't like the strobe effects in some of the rides...not a medical reason, just a preference thing... He really didn't like Spiderman but since we were all riding and I wouldn't leave him he rode as well. He simply closed his eyes and sometimes put his hands over his face to block it out. Problem solved.
Everyone has to judge for themselves and find their own balance between comfort and thrill but I think to miss these rides for anything less than a medical emergency would be a shame.