We just got back from Disney and previewed this ride. My DH gets motion sickness, and after reading the warning signs, decided to sit this out. He was smart to do so...knowing him he would have been ill for the rest of the day.
First, I give thumbs up for the uniqueness of this ride, and overall, both my son and I liked it. I really felt like I was tipping back in my seat and "lifting off" and the weightless feeling you get once you break through the atmosphere is very realistic. A fun element is having to remember to do things as a team member. I felt a little queasy a couple times because I kept trying to check on my son sitting next to me...and you really feel the spinning motion if you try to move your head and look anywhere but at the screen. I also closed my eyes once to see if that would have made a difference to my DH if he rode, and I really felt the movement with my eyes closed so I agree with the poster that said keep your eyes open, your head back in the seat and don't look around!
My 12 yo son goes on most rides without motion sickness...except for things like the teacups. We saw the warning signs about spinning, but he wanted to go on this SO bad, we both ignored them. The ride ended, he said - WOW - that was AWESOME - gave two thumbs up, and immediately vomited. After cleaning up and purchasing a new shirt, he continued to feel under the weather for about an hour or two afterwards, but then shook it off.
I've been on Body Wars, Star Tours, Spiderman, Back to the Future...all the simulator rides...NONE of them ever make me feel the least bit queasy. You can turn me upside down in coasters, and drop me on the ToT...nothing bothers me. But, I did feel this one in the pit of my stomach a couple times...I believe because of the spinning motion and my desire to check on my son, so I moved my head and leaned forward slightly, which they say not to do. (I'm dating myself - but I think it's like the "Round Up". If you lean back you don't feel the spinning motion at all...but if you lean forward and fight it, you get nauseous.) For me, the feeling didn't last beyond a few seconds, but I think people prone to motion sickness would definitely be affected.
Note that you really can't touch or see the person next to you...an important consideration for parents taking kids on the ride that they might be a little worried about. You can see their hands come out and touch the buttons during the "mission", but that's it.