PayPal does NOT have single rate pricing. AmEx is 3.5%... See the disclosures at the bottom of the page here: https://www.paypal.com/webapps/mpp/website-payments-pro

That being said, we'd love to do that but you need to be of a certain size to negotiate with AmEx. Working on it.

Also - we are keeping the same rate for international credit cards, which is something that the other guys don't offer.