There's also different levels of VR. I can get sick with 3 degrees of freedom (pitch, yaw, and roll) if I move around with it on. But with 6 degrees (also includes movement along all 3axes), I'm peachy.

My best friend gets sick watching video games on a TV, but she does fine with 6DOF VR because it's the disconnect between the motion she sees and what her body experiences that's the problem