Some good info here on pretty much the same subject if you're interested:
http://www.reefsanctuary.com/forums/...ths-facts.html
And FYI quarantine works if done initially, ie before being introduced into the display. It doesn't usually work if the fish is already in the display and then moved over into quarantine due to illness. This is typically where the debate comes from but you're arguing over two different things. Also your QT doesn't have to be small, it can be bigger than the display if you want.