Stripe Connect's fee is 2.9% + 30¢ per transaction for all payment methods accepted; plus another fee of $2/user/mo for each active "merchant" on your platform.

Adyen's MarketPay fee varies depending on payment method and is about 1-5% + 12¢ per transaction. I've contacted them to ask what one could expect for MC and Visa, but Amex and Discover are 3.95%, so I imagine similar. No mention of any other fees.

So for smaller dollar transactions (~$5), Adyen appears to be cheaper. Also, they support ACH, which Stripe does not.

sources: https://stripe.com/pricing https://www.adyen.com/pricing/full-list