Speaking with experience with ACH payments (not talking about affiliate payouts ? that is a separate subject) since 1996/97 I can wholeheartedly say that if you have ANY American traffic to your sites YOU SHOULD HAVE ACH as an option for your customers.
That said, while it a few years ago was known to increase sales by 8% - 10% on your US based sales, it now has decreased. I would dare to say to somewhere between 2% - 7%.
So, if you as a program/site owner want to earn yourself and your affiliates more money ? then it is a must. Even 2% more makes a difference. IMHO and speaking from experience.
