C.W.
I don't have particular sites but if you google that site that the gorgeous dress is on and put reviews after it usually a ton of reviews that pertain to the website will come up.
*update*
I would go to outside sites, like when I get a hotel I read reviews on tripadvisor.com or something instead of the hotel's website. If there are a lot I pay attention to the most recent because the management could've changed or something like that.