It's actually one of the most important questions you need an answer to. Using the right card at the right time is where the profit is. It doesn't matter whether it's Amex, Mastercard, or Visa. What counts is what gives the best cashback or miles at the place you're buying the vgc. Some CC will give 5% back (eg, INK at office supply stores), some give less. Google something llike "best cashback credit cards" to see which are currently the best CC to use. Good luck!