It's no tjsut teh cards you use though, but in how prepared you are. For example, I have three different decks, and between those three decks I have all five civs. So in this way, if I find out the opponent is using a particular civ, I may best counter that deck with one that contains a civ best built for battling the opponent. That is why I'm so good: I'm prepared. Although I admit my three decks are not equal in strength, they are none the less fairly strong on their own.