For once, I disagree with kinky boots..I don't think Yaktrax (especially the "Pros") are utter crap..get them at right price, and they are good for right purpose...pavement bashing, getting to newsagents,etc when weather is icy. They make a real difference when used for that purpose.
In addition I have used them for country rambles without steep gradients in icy conditions, and again they make a fair difference. But don't use on "real" hillwalking, and if you do use them on low level rambles don't expect too much mileage before the rubber breaks.