Has anyone had any experience they can share buying a preowned wedding dress?

My wife to be is shopping for wedding dresses, and we are considering buying a preowned wedding dress. However, we are a little uncertain about it. Some of the sellers do not show the actual picture of the dress on the auctions. On other sites, some of the sellers are unwilling to meet with us to let us see the dress before deciding to buy. In one of the cases, a seller mentioned that the dress was never cleaned but on after we asked. Has anyone had any positive experiences or words of advice they could share regarding the purchase of a preowned wedding dress?