I don't know why you're being downvoted for this. It's clear from the article that AmEx is not really bothering to check the claims and counter-claims. When I had disputes via MasterCard, and then again via VISA, the claims were investigated properly and the documentation provided showed that very clearly.

I've heard this several times about AmEx - this is all hearsay and anecdote - that AmEx really doesn't help in disputes such as these.

Add this to the fact that AmEx is not accepted in many places in Australia and Europe (to my personal knowledge) and yet MasterClass and VISA appear to be accepted everywhere, I wouldn't use AmEx.

And now I also won't use priceline.