Zoro, because he is stronger and likely about as fast as Luffy or Mihawk due to his recent feats, also there are no stomp threads against ONe Piece that I have seen, they won alot of their battles even against Ban Mido which I will explain in that thread.
I actually think this is fairly close. Though i am not completely current in either manga, i have seen most of their feats. DGM and One piece are actually similar in the fact that the characters in both typically don't have heavy energy powers but have high tier physical caliber. I think Zorro is stronger (think) but Kanda's energy powers are better and his speed is slightly higher too though Zoro is no slouch. Both also have tremendous endurance. I actually think it is pretty close and could almost go either way but if I had to chose it would be Yu Kanda.