As a seller, the WOOOOOORST.
First, the user interface and experience is like being sucked back to 1999.
Then, if you're a seller, the cut that ebay takes is crazy. They say 10.9%, but they actually take a cut from the whole value, including postage. So if you sell a pair of shoes for $10, and there's $15 postage on top, then you're charged 10.9% of $25. Ie $2.70 fee goes to ebay. That turns into a 27% cut to ebay on the money you're ACTUALLY making. So you make a measly $7.30 from a pair of shoes. Hardly worth the effort in my opinion! So. Much. Greed.