I'm a cyclist who hates to spend 100's of bucks on cycling sunglasses only to have them fall in the street and get run over in traffic.
These are pretty good for the price.  They fit nice and are comfortable and stylish.  They are vented at top to help minimize fogging.
The only complaint I have is that if you look out the top of the lens when your head is down, there is a distortion in view at the top.
That's just a little annoying, but I'll put up with it for the price.