Luffy vs. Vergo
-IMO Vergo was a better enemy that Caesar. I think both Law and Smoker fought a harder opponent.
-Its hard for me to say who wins, But I don't think Luffy has this fight. I giving a higher chance to Vergo and here is why.
Vergo's Haki ability is through the roof.
-He is the first person we have seen that could use Busoshoku Haki on such a level, and use it so well.
-He was able to travel across a full room in a matter of seconds which threw Law off guard.
-If you were to fight Vergo without Haki it would clearly put you in pain. And you can also assume if your Haki isn't on his level it could also put a strain on your body
---We see that Sanji is having a hard time matching Vergo's kicks. And we all know how powerful Sanji's legs are.
Now You might say that Law got around Vergo's Haki b/c he cut him in half. Well cutting damage is different than impact damage.
-Luffy does Impact damage, and Vergo makes his body harder than Steel.
-In the end Luffy wouldn't be able to really hurt Vergo, But Vergo would be able to hurt Luffy b/c of his high level of Haki.
This is not a thread basing Luffy at all. I'm just saying Vergo can beat Luffy, and that since Smoker lost to Vergo doesn't mean that he is weak.
-PS. Smoker wasn't fighting Vergo at his best, he was trying to get Law's heart back
-PS. Law had to use his devil fruit to cut Vergo, and I doubt Zoro would have been able to cut Vergo