Credit cards might look pretty much alike, but our new survey shows vast differences in how pleased people are with their plastic. And we're not just talking about interest rates, which vary widely from one card to another.

The survey, conducted by the Consumer Reports National Research Center, covered 36,298 readers' experiences with 61,944 cards. It found that consumers had far fewer billing headaches and other problems with the card issuers at the top of the Ratings (available to subscribers). By contrast, some of the biggest banks (and most ubiquitous credit-card advertisers) earned scores that put them at or near the bottom of our Ratings (available to subscribers).

The card issuers that scored exceptionally well in our Ratings--USAA Federal Savings, the Navy Federal Credit Union, and a group of other credit unions--also charged median interest rates between 9 and 11 percent, compared with the 17 percent imposed by the two issuers at the bottom of the Ratings.

USAA Federal Savings, which issues American Express- and MasterCardbranded cards, earned a reader score of 95 out of a possible 100.  That's one of the highest scores we have seen in recent years. The Navy Federal Credit Union, which offers MasterCard and Visa, was also very highly rated by our readers, as were the other credit unions.

"Credit unions are run by members, so they have a vested interest in providing credit at very low rates," says George Overstreet, a University of Virginia finance professor who studies creditunion operations. "And they are more focused on keeping their members happy, while banks have to worry more about keeping their investors happy."