Out of the 2 I would say the Asus STRIX GTX 1080 is the best, it has higher default clock settings, and when overclocked it gets even higher. With the triple fan setup on the Asus, it will allow it to be even cooler, and no doubt it has the fans off before it reaches 60c, and even when they're on they're extremely quiet.
So my vote would be the Asus STRIX OC GTX 1080.