Zoro has better Adv CoC than Yamato, King of Hell cut through a giant flaming dragon and then cut through King like butter, when nothing else before had done any serious damage to him.
I think Yamato is stronger than Zoro, but because of her durability and natural strength. Zoro's Haki is probably a bit stronger, at least, if not a good amount. Still, damaging a Mythical Zoan with Adv CoC and incredible natural strength is very hard.
It will be interesting to see what power-ups Oda gives to Yamato in the future, since she's already very strong.
I think Yamato is stronger than Zoro, but because of her durability and natural strength. Zoro's Haki is probably a bit stronger, at least, if not a good amount. Still, damaging a Mythical Zoan with Adv CoC and incredible natural strength is very hard.
It will be interesting to see what power-ups Oda gives to Yamato in the future, since she's already very strong.