I love thrill rides. As far as roller coasters go, the loopier and swoopier the better. But I can't take spinning. My inner ears are apparently quite wimpy. The "teacups" in MK make me feel sick to my stomach.
I love the IDEA of Mission:Space. I'm glad it's there. I'm glad I tried it once. It was an exceptionally cool feeling. But it also made me very queasy. I knew the risks, I'd heard the horror stories, but I just love thrill rides and I wasn't going to let 500 warnings keep me away.
FYI, my father tried it about a year before I did. Spinning never bothered him in his life. He was 71 and was in between rounds of chemotherapy. He loved Mission:Space. He said if the chemo never made him feel sick he sure wasn't going to let a little amusement ride do it to him.
Contrast that with my father-in-law. I rode Mission:Space with him in May. He had already refused to ride ALL of the "mountains" in MK (including Splash!), refused Rock 'n' Roller Coaster and Tower of Terror, and almost wet himself on Test Track and Dinosaur, but he LOVED Mission:Space and the only reason he didn't ride it a second time (we had extra FastPasses) is he didn't want to ride it alone, because I was in no condition to go back for seconds. He's afraid of heights and speed but apparently his inner ears aren't affected by intense spinning like mine are.