Naturally, you want the highest-rarity armor you can get hold of, since this allows you to equip more perks that convey various benefits when worn.
Legendary: Gold background, pre-determined high-end perks. Epic: Purple background, three perk slots. Uncommon: Green background, one perk slot. Common: Grey background, no perk slots. Just like the game's weapons, each armor piece in New World has a rarity level that affects the number of perk slots it has available: Rarity and encumbrance are the main ones you need to take into account when determining your armor quality and choosing your loadouts. There are a number of factors influencing what makes up the best armor types in New World.
In New World you equip armor pieces individually to your character's head, chest, hands, legs, and feet, but there are also full five-piece sets, with bonuses for equipping a set.