I like that Amex chargeback is treated like (or is) an insurance policy on your card. So, you get successful chargebacks 100% of the time and typically within a day. They then investigate and try to claw back the refund you should have gotten or if they find that you tried to double-dip (service refunded and amex refunded) then you'll get charged again -- that will only happen if you're trying to commit fraud.
Where it shines is times where the merchants give you the run around. For instance, I put $500 down on a vehicle in a refundable deposit. When it came to cancel it, I was given the run around between dealerships and manufacturers, no one wanted to pay out. I made the effort (sent an email), and then clicked one button on the Amex website for the charge and got the money returned in a few hours.
Where it shines is times where the merchants give you the run around. For instance, I put $500 down on a vehicle in a refundable deposit. When it came to cancel it, I was given the run around between dealerships and manufacturers, no one wanted to pay out. I made the effort (sent an email), and then clicked one button on the Amex website for the charge and got the money returned in a few hours.