FastSpring charge me 5.9% + 50c
A merchant account will cost me 3% + 30c.
My software sells for $69. So it is 6.62% vs 3.43%. Actually it isn't.
The comparison is (6.62%) vs (3.43% PLUS dealing with all those VAT issues, fraud detection, fighting and/or wearing chargebacks, coding and maintaining the payment system, allowing direct bank transfers in countries where consumers prefer them, and many more things).
When you look at the service and functionality you get in exchange for paying more, you realize that in reality FastSpring actually means paying less, earning more (profit). Take a look at the FastSpring or SaaSy features pages, and as you go through the functionality and services listed, think through how much time it would take you to develop the same functionality on your own (years), how much more revenue you'd earn from day one by using this already existing global online selling functionality, how many distracting obstacles you get to avoid (try setting up on your own to accept foreign currencies and have your order page language-localized, not to mention to be able to manage global taxes and be in compliance on all global sales), the expenses you avoid taking on (you dont pay chargeback fees, you don't need the support or dev staff members you would otherwise need, you dont need to pay for file hosting), the risks you avoid (we are the merchant of record, not you, we deal with fraud and PCI compliance, you outsource to us potential company-killing risks like how credit card numbers are stored (btw we store none), the list goes on and on...
You're a mad man to pay that much. It's a right pita, but it's not worth 6% of your company.