I think the most interesting aspect of the new Stella McCartney sunglasses is that they're made from "a bio acetate plastic...that is made from 54% natural sources.". It's not something I've seen a lot of in the manufacture of designer glasses and frankly, I would like to see it more.
That said, the designs themselves aren't exactly ground breaking. That's not to say I don't like them, it's just that they're the classic sort of design that you could probably order pretty safely online and not be too worried about them not suiting you. It's a shame this fashionable foray isn't a little more...fascinating, but I guess there's no harm in investing in a timeless style made by one of the best.
More unique among the bunch - the fun tortoiseshell print in the Retro Sunglasses
The Kanye-esque Teardrop Sunglasses
My Favourite: The Cat Eye Sunglasses