Each vending option has its own strengths and weaknesses. A coin system is usually less expensive but your vends are typically priced in 25 cent increments. A card system allows pricing in penny increments which is a great benefit and competitive advantage. If current competition uses cards and can price in penny increments, you probably should too. Card stores do better if they are attended as customers may have questions, especially in their first visit. The majority of unattended stores use coin vending.