There are three main factors that you are likely to want to assess when making your purchase decision:

Rates and fees
Credit cards attract annual fees and interest charges. Interest rates tend to be high and vary between companies. Some companies provide interest free periods. Other companies have penalty payments for late or returned payments or if you exceed your credit limit.

Repayment options
Most credit card companies insist on you repaying the minimum repayment. This can be found on your monthly statement. Alternatively, they request that you repay a percentage of the outstanding balance, for example, 3-5%.

Perks
Any perks that are offered with the credit card, which can include discounts, free gifts, cashback on purchases and even simply the prestige of owning a certain card.

Deciding which card
In deciding which card is the best for you, you will need to assess how you use the card. For example, if you use the card for convenience shopping and would want to repay the full balance at the end of the month, then cards that offer a long interest free period with no annual fee could prove more appropriate. If you use the card for ongoing borrowing, and intend to pay off the minimum amount every month, then a shorter interest free period with lower rates might suit you better. If you travel frequently, it may be worth considering a card, which allows you to pay your bills via direct debit.