Ummm, as a rabid Thor fan, I think current Odinson would and should lose to Superman, as he no longer has Mjolnir and loses flight (he can still fly, just not Mjolnir fast). I could go on longer but it basically boils down to this...
Without Mjolnir, this fight is going to get physical and fast. Supes is still stronger, and now that Thor cant fly as well, his speed advantage will really come into play and unless Odinson can get a hit in with Jarnborn, he is going to lose.
Superman 7-8/10
Unless we are talking current Thor, who is Jane Foster w/Mjolnir, who is now sentient and tells her its powers, and she can use it to speedblitz now and she has been extremely badass with it. And BFR is on tablewhich is a bad idea with a Thor fight.
Jane Foster via BFR 8/10