I enjoy it, but I don't get motion sickness. If you do, avoid it. If you're claustrophobic at all, definitely avoid it, as it's a very enclosed space and your cabin-mates will be at your mercy if you freak out.
Some people who never have motion sickness on any other ride experience it on this one, so there's no guarantee. I will say that if you ENJOY the feeling of deep pressure on your chest (the kind you get from high speed roller coasters, those rides where you stand in the round room and the floor drops out, or the round-up type rides where you stand in a cage and are held hard in position by the force of the ride twirling), then you'll probably be fine, and the physical burden of the ride won't overwhelm your enjoyment of the whole package.
I don't discount the number of people on the boards who relate their sickness stories. However, in riding it 10 times or so I have to say I've never seen anybody get sick and the usual exit-ing conversations I've overheard have been strongly positive and not complaining. Chances are in any thread asking how bad a ride is, people with negative experiences are going to be more highly represented than their actual numbers, so I wouldn't write off any experience (restaurant, hotel, ride) without looking closely at the reasons people give and seeing if they apply to you.