I dislike that there is no way to disable or turn off notifications, which are very annoying in my opinion! They also tend not be updated for long periods of time so it's hard to keep up with what you can do/pay out through them! It would help if they had an easy process where we could go live without having people ask us questions about our setup etc., but currently everything needs someone from their team getting involved because some things don't make sense at all (i've spent hours trying different setups before asking). We use megasysts payments as one method to receive payment when purchasing software subscriptions via Gumroad using Paypal Recurring Payments subscription model. Their team is very supportive. They helped me with a billing issue I was having and even called me to make sure I was satisfied with the solution. I think their customer service could be a little better. I have not used their API yet, but I plan to use it on a project I am currently working on. I am trying to get a billing system up and running for a project I am working on, and I think they have a very good system.