My vote would be for Oedipus. I would rather have a leader with some initiative, one who is willing to work and to put his mind to improving society as a whole. While he is easily angered and ambitious, these qualities would be more easily directed and channeled by a couple of right-hand men (or women) than Creon's arsenal of faults.
I can only comment on Creon because I'm more familiar with Antigone than with the other plays. In Antigone, Creon is a horrible leader. He is too afraid of anarchy to be a very effective ruler. He makes pronouncements without thinking of all the consequences. Why didn't it cross his mind that Antigone and Ismene might want to bury their brother? Why didn't he imagine that Haman might actually be in love with Antigone and take her side? Creon had power thrust upon him, and he didn't handle it well.
Comparing the two men as kings in the two tragedies, it's clear that both Oedipus and Creon suffer from too much pride. However, the basis for their pride and the results of it differ.
Oedipus is determined to avoid fulfilling the famous prophecy regarding his fate; therefore, we can see his pride in believing himself greater than the gods themselves who have decreed this fate. On the other hand, as king of Thebes, he also sees himself responsible for saving his city from the plague, and he perseveres until the unfortunate, awful truth unfolds. Pride leads him right into the fate he thought he could avoid; thus, he learns man cannot disregard the power of the gods. As king, though, he does nothing consciously to harm his people.
Creon's role as king begins with a cruel edict forbidding the burial of Polyneices; his action defies Greek custom and obedience to the gods. This deliberate act and his stubborn refusal to rescind his order to let Antigone die eventually lead to the deaths of his niece, son, and wife. Creon is a selfish king whose excessive pride does damage others. He, too, learns a harsh lesson to submit to the wisdom of the gods.
That is a difficult question to address because both men suffer from an abundance of faults. Creon is lazy and over-indulged. He doesn't want power, by his own admission, because that would add responsibility to his otherwise graced lifestyle. He just wants to enjoy being rich and well-known.
Oedipus is happy to wield power and takes responsibility seriously. However, he is impetuous and easy to upset. He has a fierce temper, and these frailities have led him to the tragic outcome of his life.
So who would you rather have? The coach potato or the capable but tempremental? It all depends on your definition of a good leader. Decide on that first, and then look for the man that best fits your definition.
That being said, keep this in mind. Oedipus is made to be a tragic hero. Creon is the leader in the end, and the few things he does, he does with foresight and compassion. It would seem that Sophocles had some clear thoughts about the better ruler!