Bought these to replace some awful checkout rack sunglasses. Night and day difference. Quality is the name of the game here. The lenses, frame, and case are exceptionally well made as should be expected for eyewear at this price point.
Switching lenses (it comes with two sets) is an absolute breeze; I have a hard time thinking of a more elegant solution short of having the glasses just do it for you. The fit is comfortable and avoids any harsh pressure points (I have a very large head so glasses frequently fit too tight). The field of vision is great though not as unobstructed as something like the Pivlock from Smith.
Top it off with the pretty sweet looks and you'll be one happy camper.