Glad to hear on the developer friendliness! If there are ways we can continue to improve on that front, please shoot me a note: lachy@stripe.com
I'm curious though what you mean when you say Adyen is much more "bare metal" than Stripe. We don't typically talk too much publicly about our underlying infrastructure (our goal is to abstract away that [hopefully] unnecessary complexity), but we do strive to be as close to the bare metal as possible. (We're directly connected to all of the major card brands, and have "acquiring licenses" in numerous markets.)