I've just started using Auction Ninja, and while I've only had 5 experiences, they have all gone smoothly. The items match the descriptions, and pick up is simple. No issues so far.
Recently, I had to leave town suddenly and couldn't pick up a big cabinet that day. AMY, who managed the auction, replied fast with some solutions. She was really helpful in making sure I got the cabinet on short notice. Much apreciated!
Overall, it's been good, and I'm looking forward to my next auction.