I own 'em.
I do like them, but you have to guard your expectations carefully. I think there's a scientific statement about how form follows function. Seen those crampons with the deep, triangular spikes? Well, obviously those are going to give you a whole lot better traction in serious snow on the side of a hill than these will. I bought the Yaktrax for running on snowy or icy side walks. They do great for that. I do take them backpacking when I know I'm going to traverse a glacier, but they don't take the place of crampons. The combo of Yaktrax and trekking poles has gotten me over a simple glacier or two, but if I knew I was going to be in serious snow, especially when hauling elk quarters, no way would I trust my life to 'em.
I like how much lighter and less bulky they are in the backpack. Not to mention how little I'd like idea of crampons tearing up my bag or back.
