pro, cooler (temp wise) inside. possible cosmetic benefits (depends who's lookin), cooler temp means A/C doesn't have to work as hard. Helps protect from that first opening the door and sitting in an oven for 10mins

cons, some people think it's stupid, of course that doesn't matter cause it's your car. if it's too dark you'll increase your chance of getting pulled over.

I say, make sure it's legal and do it.