Personally, I think that it's okay. The items range from really shitty to high end. I think that if more people were to join, then you could find cheaper, nice items.
Some complaints I have is that the support team is useless. They just quote their policies. It's retarded. Besides that, it's buyers beware. I've seen some "I HATE LISTIA. I KEEP GETTING OUTBID" or "SELLERS WERE FAKES". Well... yeah. It's like ebay. They have proxy bidding and scammers out there. It's called the internet.
I recently won a Victoria's Secret Tote thing for 2300 credits or so. I think its like 1500 credits for about 5 dollars or so. If you base it on that, then you can get this bag for like 10 dollars. Considering how VS charges 35+ per bag (ridiculous), it's a good deal. I'll let you guys know when I receive the bag. For now, here's a pic: