[Wintamute]

I am pretty sensitive to motion sickness ... get sick easily in cars, awful in boats and have suffered week-long bouts of pretty nasty positional vertigo a few times in my life but I can stay in the Vive for hours with no ill effects at all. It doesn't feel like my vestibular system is under any sort of stress at all, the tracking is super tight. My assumption is that the majority of people that experience nausea do so due to either defective hardware, or under-powered systems.

[sergiosgc]

I think it's the games. Room scale games, like Fantastic Contraption, induced no motion sickness on the twenty or so people I had trying it out. Games where your avatar is moving but you physically aren't are dangerous territory. I never tried HL2, but I easily imagine it begin nauseating.