armored uniforms have two stats, Armor and Protection
Armor is essentially a second layer of health; when taking damage, it's first applied to your armor, which is worn down by taking damage. When it reaches 0, you start taking health damage.
Protection is a passive damage absorption bonus. If a uniform has 10% protection, then all incoming damage will be reduced by 10%, even after your armor breaks.
Raw damage doesn't matter as much as you think, and DPS is only slightly more relevant. In my experience, firefights are won one of two ways; either you're a better shot, and can consistently land shots on a player's head, or you have a weapon that can provide a higher volume of fire to chip away at their health and disorient them.