These Raid Vendor Armor Sets are gear sets designed specifically to help you progress through the end game raid experience. The sets for each faction have very different visuals even though most of the sets names seem similar.
These armor sets are all level 50 and are purchased using Plaques of Achievement and Glyphed Armor pieces. The Plaques of Achievement are gained through completeing daily dungeon quest and defeating the dungeon bosses. The Glyphed Armor pieces are dropped by mobs inside of the raid instances.
Some callings have more sets available to them than other callings. This is because the gear sets have stats that support the player taking certain roles within the raid (DPS, Tank, Healer). There is no visual difference between the diferent sets within a calling, but each set's supported role will be listed for clarity's sake.
The Defiant Raid Armor Set Vendors can be found in the Catari Command Center in the right underground wing of Meridian, around 6104, 913, 5081. The Guardian Raid Armor Set Vendors can be found in the Lodge of the Plains, around 7594, 869, 3100.