This is my first pair of any type of "stability" clothing and I'm not sure of the exact benifit, but they fit really well, are windproof in the front as advertised, and are warm. I've used them in 28-30 degree temps for running and I am pleased so far.
Did a 6.25 mile run in them today and I think there truely is a benefit to these. My legs feel a lot better than usual when I do this run and I think it is because of the stability provided by the tights. We'll see how I feel in the morning!