Ok, today was my first jog wearing Yaktrax. We had a few additional inches of snow overnight, so the surfaces were mostly snow or ice-covered snow with a bit of bare pavement.
I thought they worked quite well. I did skid a couple times when I came across some ice hidden by the snow, but overall they did pretty much what I was hoping for. They even worked well during the brief periods where I had to run on pavement. Admittedly my pace was not much better than my last run without Yaktrax (about 10% slower than usual), but my confidence in staying upright was increased and I did less tiptoeing.
It's only been one day and I am admittedly a jogger, but so far I'm glad I bought them. If I was trying to do 6:00 miles with them, I think I'd have to be sure there was no ice, only snow.
Thanks again for all of the feedback.