I've actually had pretty good luck. I try to be honest as possible including any major flaws when I sell something, and I haven't had any unhappy buyers yet. I also make it clear that I will not ship anything until I have received payment. I had one guy who never paid me for an engine he was supposed to buy, kept saying the check was in the mail, and I said I'd ship as soon as I got the check......he stopped returning my emails asking about the payment, and I re-listed the engine. I'd only worry about trading on here, personally.