I picked these up on SAC, it's always a gamble to buy glasses online because they can fit so differently. These are the perfect frames for me. I have a relatively slim face and they fit and function perfectly. I've used these on a many runs, 20 road bike rides, backcountry and in-bounds skied in these and they are great. They haven't fogged up even when skinning up 6000' in the sun.
I have to disagree with previous reviewer, I did a tomahawk fall skiing and these thing stayed on my head. I punched my face right into the snow too.
I haven't changed lenses yet so I can't comment on that.