I received one of these as a member of the Endurance Films racing team and I honestly couldn't have been happier that this was one of the items they provided us with. Over the last two years I have used this sweatvac headband on countless runs and in at least a dozen winter running races without fail.
I have been able to run with this headband down to 15 degrees and it has kept my ears warm and toasty without causing me to overheat. I tend to generate a lot of heat when I am training, especially running, so a typical beanie isn't an option unless it is REALLY cold. No matter how much I sweat I can never tell how wet the band actually is until I go to take it off after a run. Furthermore if at any time I need to take it off because it is too hot during a run I can simply put it around my wrist in a figure eight, which is simple enough that it can be done while running and without slowing down.
Throughout all of my training and racing over the last two years I have yet to have any issues with movement or chafing and it has been through the wash more times than I can count. It still even looks brand new! I wouldn't change a thing about it, perfect in every way.