Advantages

• You don't need to have a separate pair of sunglasses, one pair does it all.
• They cut out up to 70% of the light.
• They protect the eyes from glare during driving on sunny days.

Disadvantages

• There can be a delay when you move suddenly indoors or driving into a tunnel (2 - 3 minutes). So care is needed in these cases.
• These lenses always have a very slight tint remaining during the night or in doors. Certainly it's never a problem as far as vision is concerned.