I think the article is pretty good because they didn't filter out any of the silliness on the part of some of these people. It really shines through to us rational types and this piece gave me the biggest laughs I had today.
Also I don't know the details (the year and more details about the location would help) but there is the chance that that one carrier used different frequencies to the others. People, their dental works and medical implants will all resonate at different frequencies. However if it turns out she was reacting to only one carrier's AMPS towers (all US AMPS ran on 806-896 MHz) it's total BS.
Keep reading. The article doesn't even come close to endorsing the people interviewed, and if you read between the lines it's pretty clear the author thinks they're all nuts.
That's where I stopped reading.
Shame on the Guardian for giving these anti-science reactionaries the platform for seeking the attention they so desperately crave.