Clean, easy to use. Needs a better directory, or categories of what is available. After 48 hours of tinkering, I like it. Adding an auction feature would definitely start cutting into eBay/PayPal's monopoly.
We have created a listing offering escrow/mediation service. Just search for CoinPro under listings. We will rebate the .0015 to the first 20 users that leave positive feedback.
The problem with a decentralized auction is, that the winner doesn't have to pay. You will have a lot of auction crashers. The people who really want to buy stuff will hardly get them. I mean, you even can write a script, that always offers 1 $ (edit: sorry 0.000whatever BTC) more than the last bid at every listing. Kind of OB DDos attacks for the lulz.

Dont get too hung up on online auctions guys, they are cool on ebay and that but mostly works best for used goods aswell. Buy it now market place is a perfectly decent option on its own.