The biggest threat to Superman here is Dooms magic, not Dooms energy blasts or Magnetos magnetic bolts (or tossing metal at him). Without Dooms magic, Superman beats both almost every time (hard fought battles all tho). With magic in the mix, if the team works together, and plan a specific assault, I think they can win, but since thats not likely to happen (or cant happen in a POOF type battle), I see Superman winning more than losing in the end.