What does the company do well? The best thing about FastSpring is that they support any country. Allows PayPal as withdrawal method.
What does the company not do well? No way to charge extra charges for the subscription. For example, I can not provide pay per use plan with FastSpring. Also, proration is kind of weird where they refund a certain amount and then charge the remaining instead of just charging a difference. Pricing is very high compared to other payment providers, but worth it if you're from countries where other payment providers do not provide services.
What do you wish you had known about the company before using? Very easy to handle subscriptions with FastSpring. Not much of a setup is required.