Regular sunglasses: please be pretty (comfortable is a plus).
Running sunglasses: please be comfortable. That’s all I care about. I need my sunglasses to be comfortable to wear, to forget they are there, to stay in place through the whole run be it on my eyes or on my head.
I haven’t owned many pairs so I don’t have much ground for comparison, but I’m very satisfied with this pair. Besides they are Ironman, so maybe I can fool someone into thinking I’m actually one?