I think that most important for shopping sunglasses is comfort. If you dont like wearing them or are too tight, you're not gonna be a happy camper. Second behind that is probably the quality of the lens. You only get one pair of eyeballs in your life so you gotta take care of them. I've been lucky to find a pair of Spy Optics that fit my face very well and are amber tinted so i can darn near wear them from dawn to dusk with no visual impairment. Plus I can be going WOT and look back and the glasses dont get sucked off my face