I've sold many scrap gold lots over several years to this buyer on ebay without troubles (just checked and it's 23 lots back to April 2010 - records before that are less easily accessed). Always set at fixed price with immediate payment required. Have always received prompt postive fb comments. On one lot only was there any sort of hiccup.... an unmarked, badly worn/damaged antique 14K watch chain with various attachments.... I missed the fact that one large end link was in fact 9K gold - a quick, easy and fair settlement was negotiated.
I think what's being missed here is perspective. 70 some-odd negative comments left amongst a total fb left of 74,000 doesn't seem at all unreasonable to me. This buyer has been high bidder/buyer of 1753 ebay listings in the past 30 days alone (he's clearly not been banned). I don't see where honest/competent sellers need worry about this buyer.
ps- This is my first post here. I've been avidly reading and studying here for the past couple of months. I will properly introduce myself within the next few days - just felt the need to jump the gun and post my experiences with this buyer.