Withholding Feedback on eBay

Ran across this interesting article that gives good advice regarding eBay feedback. I've been involved with eBay transactions where things have gone awry (i.e., ordered one thing, got another) and have refrained from leaving negative feedback on eBay for fear of retaliating negative feedback. But is that the best move? (Source: O'Reilly, see O'Reilly Hacks)