First off, there is no accounting for taste. That being said, I prefer Kefka myself. Perhaps its because he reminds me of the Joker from Batman. There's just something about that random maliciousness, and your not ever sure what he takes seriously. Also, I like the curiosity about human emotion that he has while at the same time trying to destroy it. He's a very simple villian in that his motivation is only to destroy that which he does not understand. Yet he is tragically bound to the human race even as the god of magic in the end. He's not evil just to be evil. He's not part alien. He doesn't think he's doing this for a greater good. He's just all the bad parts of humantity. Kinda like if 4chan was sentient.