User Review: Kahtoola Microspikes
Price Paid: $59
The Kahtoola Microspikes made running in the snow and ice feel as natural as running on a dry road. I love them -- and they're easy to put on. (I shot a short video and included some add'l details at my site, therunnerstrip dot com, if you want to see more).
My only caveat is they wouldn't work well in deep powder, or on surfaces such as plowed roads that will have significant stretches of pavement. You need a minimum amount of ice/snow underfoot to make them work.