My wife uses Ebay a lot, but I don't like it.
I set up an account and bought an item once, and had some issues with the seller getting the product to me. Took the money right away, but took forever to deliver, was difficult to contact, had a laundry list of excuses of why she didn't ship, and generally had lousy customer service. She was one of those part time sellers out of her basement. I eventually did get the product.
So I left my feedback based on my experience, and her feedback slam was not to pay attention to an ebayer with only one purchase under their belt because I didn't know how the system worked. She was right, I expected good customer service without a bunch of bogus excuses, like I'd received for years from legitimate, non-ebay online retailers.
Then my wife told me about the little "housewife selling crap out of the basement click" that runs rampant on ebay, and that if you leave honest feedback about these sellers, they get catty.
I haven't used ebay since - don't have the tolerance for that kind of crap. We also had folks trying to hijack our Paypal account a number of times in one year, so I will not deal with any online retailer that only takes paypal and not credit cards.