I was on there for a very short while. I was only selling a few destash bits and bobs. I watched several auctions before deciding to list my stuff, as I wanted to see what kind of prices things went for (lots of 'vintage' keys went for over $40

). I listed and sold 3 or 4 lots (only one person didn't pay up, but the site is quite clear - you try to contact them again and if they don't respond in a few days, you can cancel the sale and leave them negative feedback, which I did). It was just taking off when I was listing, and it got very popular once the Etsy crowd joined in, so it was really difficult to find a spot in an auction.
However, I was put off using the site when I discovered that the buyer of one of my lots was relisting the items (no problem there)...using my exact text and photos.

I did a double-take, as I thought I'd somehow relisted the items myself. I contacted staff to complain and they did respond, but because there were a few hours to go to the auction, they weren't able to (or didn't want to) make the person remove my text and images and do her own. It might seem a small thing, but it put me off somewhat.
I have bought a couple of things without problems, but I am trying to clear some stash before buying more stuff.
I would be wary of selling anything that has a high value or that you have invested a lot in (emotionally, I mean), as I have seen lots of really nice stuff (mostly jewellery) go unsold, or for stupidly low prices, as the recommended starting bid is half the retail value. I know some people on Etsy have had to sell at really low prices, and they aren't happy about it.
I'm opening a destash shop on Etsy instead, as I feel I have more control over what I'm doing, and I can list whenever I want, rather than waiting days for a slot to open up.