Banks also offer low rates. "Credit union rates on their cards are on average less than bank cards, but it's not like they're five, 10 points less," says Curtis Arnold, founder of North Little Rock, Ark.-based CardRatings.com and author of "How You Can Profit from Credit Cards." "I see a lot of credit union cards that are right around 12(percent), 13 percent."
So, make sure the APRs at credit unions for which you're eligible really do have better rates than those offered by banks. Arnold cites Simmons First, an Arkansas community bank, as an example of a bank that offers a rock-bottom APR -- 7.25 percent on its Visa platinum card.
"Consider all your options," Arnold says. He urges revolvers to look for the lowest interest rate, regardless of the issuer.
Few options for "bad credit." If you have less-than-average credit you may have trouble qualifying for most credit union cards, according to Arnold. "Before I applied, I would make sure my credit was good, 730-plus on FICO." You can estimate your FICO score for free here.
If you have poor credit, look for a credit union that offers secured cards, which are backed by a collateral account funded by the consumer in case of default. The deposited amount usually sets the credit limit.
Ho-hum rewards. "The rewards cards usually aren't as aggressive in terms of a rebate. You're going to get 1 percent cash back or 1 point per dollar spent -- usually pretty plain-Jane, no-frills kind of rewards programs," says Arnold.
"If you're not revolving a balance, unless you're getting dinged with a lot of fees because you're paying late or whatever, then usually it's not going to make sense" to go with a credit union rewards card, he says. "As a general rule of thumb, you're better off shopping for a bank rewards credit card program."
Shorter customer service window. You may get a warmer reception when you call customer service, but smaller credit unions may have limited hours of operation. Make sure you check customer service availability as you shop around.
Create a news alert for "credit cards"