In regards to the American Express immediate charge back with any customer request...they told me that it was because I'm a internet based business. Their argument is that because I don't see the card and therefore no opportunity to ask for supportive ID that I'm likely to incur more fraud.

Thankfully, I've only got a couple customers that require that I accept AmEx so I fall under the $5.00 a month program. Once that goes away, so will I.

We're with NPI and although I'm somewhat happy, I do shop from time to time. We only accept VISA, MC and AMEX and VISA is the most popular card. Most of our Universities use Visa (they call it the P-Card for Purchase) in place of purchase orders now. Really helps the cash flow but boy do the credit card servers nickel and dime you to death. And, it changes on the fly. Although my average cost is 1.7%, by the time you figure in everything, it's darn near double that.
Still, you almost have to accept them if you work in the corporate environment.

Paul