I noticed that there was some misunderstanding on how armor is used in the game and I hope to clear that up so you can make more informed decisions in the gear you wear:
AR is used to calculate the chance that an enemy strike hits your armor instead of you directly. An AR of 100 means 100% of the hits to you should be mitigated by armor. An AR of 50% means half of the attacks should be mitigated by armor.
Damage against you is reduced if an enemy strike hits your armor. The damage mitigation value depends on the type of armor you are wearing:
So, if I am struck by a melee attack and it hits my armor and I am wearing plate armor, 35% of the damage will be eaten up. That's a lot!
Shields are a special case. If your shield blocks an attack from an enemy, it will absorb a % of the damage equal to its armor rating. For example, if my shield has an AR of 10, then 10% of the damage will be mitigated. If the AR is 75%, then 75% of the damage will be mitigated!
In PVP, AR effectiveness is decreased by 50%!
Some more info here: https://realmserver.com/forum/announcements/game-update-notes-05-18-2018