When buying, perhaps unfairly I always read the negative feedback first, and over the years I have found that this is often in the seller's favour. Why? Look at what the complaints are about. Silly things sometimes, really poor grammar and spelling often - though don't judge by that alone - and quite often positive feedback amazingly left 'by mistake' in the wrong section.
Negative feedback often gives fair warning not to but, but not always. I have never sold and don't want to because of disability, but generally I have found the long-suffering sellers are honest and very genuine.
In all the years that I have bought from eBay sellers, I've left negative feedback twice and never lost money thanks to the sellers and to eBay.