I can't give you all the specifics, but taking cards has allowed me to function WAY better as a business. As of about 6 months ago, I started strictly enforcing the payment up front, or at least at the time of pickup rule. We had EVERYONE and their brother in this town owing us money, and they always took forever to pay, cause they already had the product. It got to the point where it was effecting how I was able to pay my bills, and I'd have to start paying interest on stuff that was late etc.
Now, they know they'd better bring a check, and if they couldn't get one, they pay w/ a card. I started tacking on just a little more to my quotes for corporations, and people I know will be paying w/ a card. I don't add a "card fee" I just make sure and throw in another $10 on top of my price to cover the fees, not that it really matters anyway. I just mainly raised everything across the board, and that covers the money that I have to pay on their transaction.
I love taking the cards...hate paying the fees when they are huge, but I get my money, and I haven't had such a hard time running my business having working capital around now.