Should I Debate a Calvinist on the Problem of Evil?

So far two people have responded that they would debate me. One is a Calvinist. To debate a Calvinist on the problem of evil is an open and shut case. All I have to do is to ask the Calvinist why God prefers a world like ours to a world where everyone obeys him. Now let's say a Calvinist offers an answer and is unconvinced by any of my replies. I never said I could convince those who hold to absolutely idiotic beliefs such as this one, that they are wrong. Any thinking person not already blinded by their faith would see the obvious and serious problem here. Why does God prefer this world to that one? Answer this if you can.