I had an extremely bad experience with the repatriation coverage (AXA) of my AMEX gold card when dealing with a serious disease in china a few years ago.
Hopefully I had a Visa Premier and they handled professionally the payment of the local hospital bills and the repatriation in business class on the first direct flight available.
Would not recommend AMEX for the travel insurances (in France at least). They are extremely bad (one of the reasons I switched to the basic Blue card).