If the company you are working with can accept the credit cards, and the fees incurred do not reduce your percentage, then go for it. Our school district offered the option for online food service accounts and they charge and additional $1 for the credit card option. (I'll stick with checks.)
I know that when we started accepting credit cards during our book fairs our sales really went up. That was easy though because the book fair provider handled all of the credit card issues and fees, we just ran the slips.
We set up PayPal to accept credit cards for our PTO. I've posted a few times on my problems with PayPal (eg, they wanted my SSN or credit card number to allow me to transfer more than $500/month from PayPal to the PTO bank account; they wouldn't accept the PTO's EIN).
PTO Today has an affiliation with PaySchools, which has a slightly higher fee percentage, but may be easier to do.
I would like to start excepting credit cards at school. Given the credit card time, I feel it would boost sales on Spirit Items and for Catalog sales (Fall Fundraiser). Has anyone done it at there school?? I need info. Thanks!!