[jlaurend]

You can negotiate with Stripe if you're at high enough volumes. It's likely that the "best" choice of payment processor is heavily dependent on the specific business in question. If you need agility and developer friendliness, Stripe is hard to beat. If you're trying to grind out every last percent of margin, you'll have to shop around and see what you can negotiate (and the offers you get will likely depend on the nature of your business, chargebacks/fraud, etc).