I don't personally request payment on sale as I feel it restricts the market, but I offer other payment options as well and base my decision on allowing a customer to buy, and then pay through whatever option they prefer.
If I was to request instant payment upon sale then I would be restricting my sales to PayPal customers only.
I leave it the required period of 96 hours, send two payment requests within that period, then if no payment or correspondence is received I file an eBay dispute to reclaim the sale fees, and then block the bidder so they can't stuff me around again.
I tried searching for links to confirm any additional fees for sellers accepting credit cards and/or other payment options but I couldn't find any.
Personally, I think offering additional payment options is a good way to attract buyers - more options is often better! A number of people are not very keen on using PayPal these days due to their rising processing fees..:( So credit cards may be good for your listings whether your a small or big time seller, so long as you sell constantly not just whenever you feel like it.
Hope this helps.