Re: Thor (from TDW) vs Superman (from MOS) who wins in a fight, and why ?
In the comics, Superman can't wield Mjölnir naturally. The one time he did, it was because Odin lifted the restriction due to the critical situation. I think the reason Superman can't consistently lift the Mjollinir is that he's too strongly against killing and the Mjollinir was made for killing enemies.
Though maybe, if this is also true for the movie universes, for this reason, MOS Superman would be able to lift the hammer (you know what I mean :P).