Well Doom is my favorite Marvel villain so he takes it for me. He is just as complex as the Man Of Steel. Superman is great in his way too. I just cant stand the DCEU version. Most wanked version of Superman up to date.
Superman. I've never been the biggest fan of Doom. He always seemed bit to broken to me. The way he'll just pull out random magic tricks, time machines, etc... And then still somehow lose to so dumb shit.
Doom is a cool villain. But Superman, something about him is so appealing. He will always save the day and if he fails he'll try again. He gives a shit about everyone. Being so simple makes him pretty complex, funny enough.