Stripe is a game changer. I've been using it for a few months and honestly its the best API I've ever used. The documentation is clear and concise. Its customized to your account so you can literally copy and paste and see the result. Just like it says, it gets out of your way. I was up and running and accepting recurring payments in less than an hour or so. I actually began to think of larger "swing for the fence" type of ideas that I would have never considered if I were stuck to using Paypal because it was so painless. Looking forward to them eating every other payment processor's lunch.
Anyone know whether they used a documentation tool to generate the 'example on right' style pages? E.g. https://stripe.com/api/docs?lang=python#delete_customer. It's very clean. The general layout and feel of the API doco is great.