As a person who has bought and sold over 1K items on ebay, over the course of more than a decade under 3 different accounts, I will have to say that disputes and misunderstandings, as well as outright fraud, can work both ways.
I can say, for certain, that ebay tends to be biased for buyers and against sellers, in general, and that punishing sellers is easy:
just snatch the money out of their Paypal account and hand it to the buyer.
What to do about dishonest buyers? There is very little recourse for sellers there.
"Item Not As Described" is a pissing contest, no matter who happens to hold "the truth" on their side, if you are speaking in terms of appearance or condition.
It is a different story if you ordered "A" and received "B" but the seller is in a very weak position to defend himself since all of the evidence is out of his hands. I have been scammed by a buyer who said that what he received was not what I had sent to him. It was a blatant lie but there was nothing I could do about it to prove my case.
Last, I believe that if an item is accurately described, securely packaged, and properly posted to a verified Paypal address, then the seller has faithfully discharged his obligation and the buyer needs to accept what happens from that point.
I understand that I am in the minority on this point, perhaps because I have sold more than I have bought, but I do not feel that a seller should be held hostage to the buyer's complete happiness and satisfaction, if he has done his duty in good faith.
