I lost $1800 to DSSMAN last summer with the phony COD check. It taught me that 1)a phony COD check looks pretty darn good if you only glance at it, 2) that anybody who wants to pass off a phony cashiers check for COD can, and 3) if you receive a phony cashiers check as payment for COD, the only real retribution you have is to spend a lot of time talking to law enforcement agencies about how they can't do anything for you. Mind you, they were very attentive and responsive, they just truly couldn't do anything about it.
I probably won't do COD as a seller again, based on the fact that I have positive feedback here and on ebay established over a couple years and that I'm easily contactable and verifiable that I am who I say I am. That said, I might do it again as well - in retrospect, I probably broke every rule about insuring a positive transaction that I have ever defined in getting burned. Almost any of them, if self-enforced, would have allowed me to avoid that. IOW, shame on me.
I didn't have a transaction for many months after DSSMAN, largely because I didn't want to buy or sell anything, but partially because it left an obvious bad taste in my mouth. Recently, I both bought and sold items over $1K and both transactions went totally smoothly and were very satisfying. Once again capturing the good feeling of getting great performance for a fraction of the cost and remembering that I've saved oh so much more than $1800 through this type of transaction.
The bottom line, for me, is protect yourself every way you can, recognize that there will always be risk, and never make a deal that puts you in a situation that you can't absorb if you do happen into a rip-off. -Kirk