As commander of the 5th division of the Whitebeard Pirates, Vista has authority over the lower-ranking subordinates. He 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. Since he was the one individual Marco specifically commanded and entrusted to protect Luffy from Mihawk, he is also likely the strongest swordsman of the Whitebeard Pirates; this was also stated in a filler scene by Mihawk himself.
He has incredible strength and reflexes and is also able to move very fast since he immediately backed up Luffy against Dracule Mihawk. He was capable of deflecting an attack from an axe-wielding giant, as well as easily slice down cannonballs in midair.
Another indication of his strength is that during the Battle of Marineford, despite having fought against individualShichibukai and admiral members as well as numerous Marine officers, he sustained no significant injuries.