Forum Moderators: buckworks
I can recommend element5 / DigitalRiver. They are specialized in software registration. I don't know if they do simple transactions as well. But they seem to be the most complete when it comes to worldwide payment methods. They even handle payment via invoice and cash payments.
In Germany, credit cards are not that widespread. We like cash cards very much. Commercial customers expect to be able to pay by invoice. The most popular is still wire transfer (we call it "Überweisung"), since no bank charges apply.
P.S. They are the ones behind ShareIT.