Zoro would win, the only thing he couldnt tank is TBB and possibly Lariat in version 2, though to be honest, with Zoro could easily out maneuver Bee in his full Hachibi form, and slice off his tails one by one taking massive portions of chakra away from him as Sasuke did with his electricity spear. But thats an assumption but going with facts if they where to engage in a sword fight Zoro would easily win with the fact his swords are heavier and of better quality.
And in Bees hachibi form it simply provides Zoro a larger target, and the fact that Zoro has effortlessly been able to cut through a galleon, dodge lasers from a Pacifista cyborg and incapacitate it with ease despite the fact that its alloys are much more sturdy than steel, proves to his strength an maneuverability something that Bee doesnt have.
But honestly I find it funny how we're comparing a top tier naruto character, one of the strongest in his Universe to Zoro whos strong but is not even near the strength of a top tier character such as admirals, yonko and even some of the shichibukai and in all actuality Zoro has alot more time to improve unlike Bee whos already reached his maximum potential.
So pretty much this fight could go either way but Im tipping it in Zoros favor.