https://www.braintreepayments.com/pricing
Fastspring charges 5.9% + $0.95 (or optionally 8.9%) and then holds your money for 2 weeks at a time.
The paperwork and $35/month fee (with $75 minimum in transaction fees) are the reason that Braintree can charge their rate.
The lack of those is why Fastspring charges what it does.
@huxley - this pricing https://www.braintreepayments.com/pricing is for U.S. based customers.
@entropyneur - we've not published international pricing because we work with multiple banking partners throughout the world who have different pricing structures and accept different merchant types. We're working on standardizing this and making it easier for you. We have a ton of other improvements in the pipeline that will continually improve our offering.