I've done a number of CODs, both as buyer and seller. It really depends on how comfortable the parties feel about doing business. I really don't care for UPS COD because it takes quite a while for the deal to be ultimately finalized. UPS isn't speedy with normal type deliveries and it takes again as much time for the seller to finally get their money. On the other hand, with FedEx Express deliveries it usually takes 2-3 business days for the package to get delivered and then the certified funds are overnighted back to the seller. It's a whole lot easier dealing with those members who have a reasonable amount of positive feedback. Remember, you always want to speak with someone in person if at all possible. If you don't feel comfortable doing a deal, then don't. If you have a desirable piece of equipment and you price it fairly, there will be someone who will buy it. The terms and conditions of shipping and payment are things that can be amicably worked out.
