IMHO, if you have problem and there is an arguable case for coverage, Amex will take care of you. I remember when I bought a vacuum at Sears, hose cracked, it was out of Sears warranty, Amex immediately send me a check for the entire cost of the machine.
They appear to WANT to pay, unlike the rip-off extended warranties you can buy at Circuit City etc.
Guess Amex is thinking about a long-term relationship. @:-) The retailer and/or warranty company is not.