In a no knowledge situation, Law may have the advantage considering how tricky his DF ability is. You can't allow yourself to be reckless. However in a manga/full knowledge situation, it's different. Zoro seemed to have notice Law's ability when he used it on other strawhats in Punk Hazard, so he should be aware of how his operating room works.
I don't think long range combat would bring much. Pre-skip Zoro was capable to identify Kaku and Kalifa's cuting ability the first time he saw it, noticing the trajectory and saving the rest of the group. On the other side, flying air slashes would be useless against Law's shambles
It would come down to close quarters and in this case, Zoro demonstrated physical superiority when he managed to combat against a gravity much higher than the one that pined Law down. Along with his superior swordsmanship, his skills would put him above in close combat. Though we don't really know how Law's cuting ability would fare against Zoro who most likely also has the superior armament haki since it's supposed to be his speciality
