I've always been a bit dubious of claims by glasses such as these and couldn't see how they could actually help. I have seen some available for obscene prices, but having read reviews of them I decided to try a less expensive set.
The first thing that you notice when you put them on in low light (and especially snow) is that the landscape appears to get brighter. In reality I think it is the contrast that is altered, making details easier to discern, but it is quite a surprise regardless.
The slight yellow tint also makes oncoming headlights less severe, so you don't squint when faced with several sets of the now popular halogen lights. Even those helpful motorists that think you want to see their full-beam bulbs working aren't as much of a problem as normal. Driving long distances at night can become very uncomfortable for my eyes, and these seem to alleviate the strain quite a bit.
The label attached to the glasses also claims uv protection. However, it doesn't specify uv-a or uv-b, which is important to know; so I wouldn't want to use them as genuine sunglasses.
For use as night-time driving glasses though, I recommend them and wouldn't now be without a pair.