The UI is nice but overall the software is still pretty buggy. I don't think it will supplant ebay until it can run in a browser. Also the fact that it's really difficult to move to a VPS after installing locally is also kind of a drag. Growing pains, I guess. I do see the potential but I feel like I am running an early beta of the software.
Yeah, it's no real competition against eBay, and even if they manage to run the software all integrated in the browser as a webpage, it will not be a real competitor against ebay anyway. Most people still don't see usage in Bitcoin because they have to buy it first with fiat, so it's pretty stupid to buy with fiat the Bitcoin, then buy whatever you want to buy. Why would you do that if you can buy it directly with fiat?
Until people start getting paid in Bitcoin directly, most people will not use Bitcoin as a currency but instead as a better gold.