Kon El
Genetically Modified
The difference being that Thor isn't engineered to overcome any enemy, that's why.
Limitations: The Juggernaut does have certain vulnerabilities. He can be affected by mystical forces of sufficient strength. Without his helmet and/or skullcap, both constructed of an unknown mystical metal, he is vulnerable to psionic attacks against his mind. Nimrod, a robot from the future of an alternate Earth, successfully attacked the Juggernaut's mind and nervous system with advanced weaponry producing tight-beam high-frequency sound waves and a synapse dislocate that jammed his neural impulses.
That basically means that sonics can disrupt his neural pathways, Doomsday can allow his physiology to develop sonic blasts from his vocal chords. The difference being that unlike Juggernaught who's power relies on Cyttorak, Doomsday has limitless biological potential. The battle is a no-brainer.