eBay's own discussion forums (select 'discussions' and then 'selling' or 'shipping & returns') include a lot of horror stories from sellers on that platform. I have had a few bumps and pauses in selling a few hundred of items from Lew's collection via that platform, but no disasters yet - so - at least in the categories relevant to our field of interest - I'd say at least 99% of buyers are good. But, as there are huge numbers of transactions, things can go very wrong now and then and I'd advise anyone considering selling on-line these days to follow some of the stories evolving there and also to heed the advice given by experienced sellers.