I don't remember much about Crush's Coaster at DLP, but I'm certain that we rode it twice which means it did not make my husband ill and he's very prone to motion sickness. (I know we rode it twice because we got stuck in the queue when the ride went down at the exact same spot both times!). Star Tours makes him very sick, he won't attempt Mission Space as that would be awful, but he can ride Soarin' and Flight of Passage. Remy at DLP also made him ill so he didn't attempt that at WDW. Lots of rides at Universal make him very ill - he tried Forbidden Journey once and was still not feeling well the following day. Hopefully that helps determine if you're prone to the same type of motion sickness. Anyway, we rode Cosmic Rewind and he loved it! No issues with motion sickness for him. He did take a generic Bonine around 30 minutes before we rode but he said he's pretty sure he would have been fine without it - if anything it would have been mild queasiness.