My wife recently bought two sets for herself and me. At first I thought they were just a gimmick, but after walking the dogs around my different courses I find they are excellent for ice. We both have about 35 years of crampon experience so wearing these at first felt kind of low level technology but after the first three mile walk with our older dog I was sold.
Remember if you buy them try to buy at REI because if they don't satisfy you REI (Rental Equipment Incorporated) will take them back.
http://www.kahtoola.com/