I've been using the Anti-Glare about four months now and have not noticed any of this "nausea inducing rainbow effect".
It looks good. Go to an Apple store and I guarantee you can find a genius with one on his iPhone. That's where I got to see it in use before making my decision.
They're talking about how the anti-glare coating makes the screen look like it has some sort of glittery pattern on it. The bumps from the anti-glare coating diffuse the pixels and distorts them.