Erlang is also the death of a lot of fluff articles of late.

The thing with Paypal is that they aren't quite so flexible and they have high fees, 3 to 4% or more. My only complaint was that they are very pro-consumer, meaning they side with the credit card company when the purchaser of your goods complains, but this is normal. There are charge backs with credit cards too if you do your own processing and payment management.

Paypal is the only payment system I've used. I wish their system was easier to customize.

You may want to check out Amazon FPS, but I haven't used them.