I will start with the biggest but only negative I have noticed so far. Unless I missed it, they do not claim anywhere on their site that their products are authentic.
They do seem to accept paypal and credit cards, which is a plus.They did once use an Overstock.com auction account to sell items and they have a fairly impressive feedback. Here's a link to an old auction (google cached to show their email is associated with the site at the bottom):
http://209.85.165.104/search?q=cache:UEso3gtvLfAJ:auctions.overstock.com/cgi-bin/auctions.cgi%3FPAGE%3DPRODDET%26PRODUCTID%3D366678 18+advantageliquidators.com&hl=en&ct=clnk&cd=15&gl =us&client=firefox-a
I couldn't find any sites that claimed they are scammers or selling fakes. This site may be associated with them:
http://www.advantageliquidatorscatalog.com/
Other than that, I suggest waiting until the morning for more replies.
Edit: I have also noticed that on their retail section and the prices that their items ended for on their Overstock auctions were very low for the name. Tommy polos for 15 bucks and Juicy
Couture skirts for 30 bucks is awfully cheap to be authentic.