Not all credit cards are born equal. Different cards have different offers, features, and charges, and choosing a card is not as simple as going for the one with the lowest advertised rate. Various types of card are suitable for different types of use, and choosing the right card for you depends on how you plan to use it as well as how low the rate is, or how attractive the introductory offer.
If you intend to use the card mainly as a convenient way of spending and usually clear your balance every month, then the headline interest rate doesn't really matter to you, as you shouldn't be paying any interest at all. Instead, make sure the card you're planning to apply for has a long 'grace period' on interest charges, giving you chance to pay your statement before any interest is applied. Interest free periods should be at least 30 days and are more usually in the 50-60 day range.
This kind of card user can also benefit from a cashback or rewards scheme if the card is regularly used for purchases, and so long as you avoid carrying a balance over you can actually turn a profit from your credit card account.
If, however, you use the card as a kind of short term borrowing, regularly paying off larger purchases over a few months, then a low interest rate is attractive. A cashback feature might seem attractive if you're making larger purchases, but it's rare that a card's cashback rate will be anything like high enough to compensate for a higher interest rate.
If you want to finance a single large purchase and repay it over a year or so, then look for a card with an introductory 0% deal on purchases that lasts long enough to clear your balance before interest kicks in. Introductory deals of up to 12 months are now common.
Many people use a credit card's balance transfer feature to fund longer term borrowing. If this applies to you, then you have a choice between a 0% introductory deal or a long-term low rate. If you can see yourself paying off your transfer in the near future, then a 0% deal with a long introductory period is probably the best way to go. If, however, you'll be repaying your balance over a longer period, then a low balance transfer rate that is fixed for the life of the balance can be a good deal. Many such cards feature a rate much lower than other forms of unsecured finance such as personal loans, and you don't have to worry about finding a new 0% card when the introductory deal ends.
Most people use their card in a mixture of ways, and this is where choosing a card is more complicated. A low balance transfer rate might mean having to pay a high rate on purchases, or a card with a low standard rate might charge higher rates for cash withdrawals. Fortunately, there's a new kind of card that is becoming more widely available, which charges a simple flat rate for all use, whether balance transfers, purchases, or even cash withdrawals.
These cards often feature an attractively low rate, as there are no fancy introductory offers or reward schemes to pay for, and so they can make a very good option for the average card user.