I can understand the feeling about the bidders who disappears after winning the bid, it sucks. It isn't easy to bid at ebay, when you have a low feedback, just because there are tons of those who raise the bid and never buy or pay. I agree that no negative feedback is unfair, no, wait, it's insane.
I don't like to use ebay, but getting most of things to my amiga has been nearly impossible without it.