Vista is a very experienced veteran, as he was shown as a member of the Whitebeard Pirates from the times of Gol D. Roger. He is one of the strongest members of the Whitebeard Pirates, as shown by his position as the 5th division commander.
Another indication of his strength is that during the Battle of Marineford, despite having fought against individual Shichibukai and admiral members as well as numerous Marine officers, he sustained no significant injuries.
He seems to be a world-renowned swordsman, shown by the fact that the strongest swordsman in the world, Mihawk, commented that only a fool would not know Vista’s name. Vista lived up to his reputation as he was capable of matching Mihawk in a sword battle for a good portion of the war without any indication that he had been on the defensive.
In the anime he was also able to block bullets with his swords to protect his allies from being shot while escaping.
Vista is also capable of using Haki to fight Devil Fruit users. He is at the very least capable of using Busoshoku Haki, as seen when he fought against Akainu.