I've purchased a pair of Gucci sunglasses and a Pucci bag from them and they both were authentic. Again, if you don't like it ... u can always return it for a full refund.
I got an authentic Chloe Python Betty from them, but I'd get any purchase authenticated, here just in case. I didn't keep it because there was a screw missing from the locking part of the hardware, but it was definitely the real deal!
Actually I think the Misty bag is a legit designer in Thailand, check out this page, it tells you a little bit about them: http://www.settimall.com/handbags.html
But otherwise, yes, they sell authentic I got some awesome Fendi scarves from them for $15 a piece. And you can always send them back if you don't like them or don't feel they're legit. I don't know how you would decide to buy sunglasses online though, if you've never tried them on in person.
I have bought a Balenciaga and Gucci bag from them and also some sunnies and a wallet and everything was authentic. The shipping was fast and the prices were great. I think if you sign up for their email you can get 10% off any purchase.
I can only speak for one purchase but a Fendi Spy I purchased from Overstock was fake. I was able to ask the Fendi experts here about it and I also compared it with another Spy that I own. I was able to return it without a problem.