Force, Galen. He was lifting/moving Tie Fighters, and had brought down a Star Destroyer with his force mastery.
Lighsabers, probably Obi-Wan, then there's Galen's experience from already fighting Rahm Kota, Shaak Ti, and Kazdan Paratus, not to mention Emperor Palpatine himself.
And as for all out, Galen. No contest.
I know all about this one since I have played TFU. This is what happens:
With a force fight: Starkiller jumps into the air and somehow uses the force to make a large 'boom'. Obi-wan would be pushed back and, as it happens, he falls into lava! He tried to defend it but he was not strong enough.
Now, with swords alone it is interesting, because although Obi-wan should win on most occasions, on this one he is sick and Starkiller chops off his left hand. Kenobi escapes so I guess you can argue for a draw.
That is how it pans out. No doubt about it.