Freind of mine has fast food type place in town and resisted credit cards for long time. Finally he gave in and while it hasnt really boosted his bottom line, it is amazing how many customers he used to have walk away.
 
His usual ck average is about 5.50 on cash but right around 8.00 on credit. He says the fees eat the difference so it balances out and doesnt have any upset customers anymore. Also has no restrictions on how much to spend to use it.