Something else to keep in mind is that most credit card companies can raise your APR at anytime.
Even though right now you have a good APR..that could change quickly.

A short article to explain how these banks can rasie your APR even when you pay your bill on time.

frontline: secret history of the credit card: eight things a credit card user should know | PBS

"» Even if you make your credit card payments on time, the credit card bank can raise your interest rate automatically if you're late on payments elsewhere -- such as on another credit card or on a phone, car, or house payment -- or simply because the bank feels you have taken on too much debt.

This practice is called the "universal default" clause and increasingly is becoming a standard clause in credit card agreements. According to credit card executives, the logic behind universal default is that the bank is not being unreasonable in raising rates when it has reason to believe that the risk of being repaid by the customer has increased. [Note: Credit card banks can now easily track your everyday financial activities and monitor your credit score -- see below.]"