I'm not sure what to say on the Q-link. My wife got one from a friend and wore it for a little while--she said she didn't feel anything, she also got a skin irritation from the included chain. Since she's not really wearing it anymore, I'm going to try it out, wearing it in my front pocket.
My opinion at this point is that re-balancing types of energetic modalities, be it the Q-link or Qigong, are helpful while they are worn or done. As soon as they're stopped, the disruptive effects of the EMF will settle in again.
Put bluntly, do I think that a cell phone antenna worker wearing a Q-link and practicing Qigong daily will be protected from the massive EMFs that they have to walk into every day? Hardly, but they'll do better than someone who isn't doing anything to protect or re-balance themselves.
There is also the "intention" part of these devices. Having the intention of protecting oneself could be very beneficial--so could the idea that the EMFs are harmful having quite a strong negative effect.