Several of the big banks have, over the past year, shown a renewed interest in growing their credit card market share and figures from the Australian Prudential Regulation Authority show that both Westpac and Commonwealth Bank have grown their credit card books well above system over the past 12 months.Westpac's and CBA subsidiary Bankwest's marketing efforts have been recognised in comparison site Mozo's latest credit card awards.In the balance transfer category the top three products were Police Bank Visa, Westpac Low Rate Visa and Bankwest Breeze MasterCard.To judge this category Mozo calculated the cost of paying off an average balance of $4400 once it had been transferred on a balance transfer deal. The calculation took into account a $100 monthly payment, annual fees and reward fees, the balance transfer rate and the ongoing rate.In the fee-free category the top three products were Bankwest Zero Platinum, GE Money's 28 Degrees MasterCard and bankmecu Visa Credit Card. To be considered in this category a card had to have a minimum of 55 days interest free and no annual fee. Cards were then ranked according to the purchase interest rate and the foreign exchange margin.The best low-rate cards were Community First McGrath Pink Visa, Credit Union SA Visa Credit Card and Maritime, Mining and Power Credit Union Visa Credit Card.In this category, Mozo calculated the cost over five years assuming a continuous interest-accruing balance of $4400. Calculations took into account introductory rates, ongoing rates, annual fees and fee reductions or waivers.In the premium card category the top-rated cards were Bankwest Zero Platinum, Westpac 55 Day Platinum Visa and NAB flybuys Rewards Card.In this category, Mozo was looking for the cheapest way to gain access to premium card benefits. Cards had to offer a concierge service, complimentary travel insurance, warranty extensions and purchase insurance. Cards were ranked according to the annual fee and then the ongoing interest rate.