For pvp they both do a great job and a lot of damage from what I have seen. I have a lvl 42 stam dk but never tried a stam templar. From my experience, stam dks are more limited with their damage dealing skills because their main spammable damage ability is just wrecking blow/dizzying swing, whereas stam templars can use biting jabs as well. I have actually seen many stam templars gap close, dizzying swing, jabs, execute in pvp with great success. I truly wish stam dks were not completely dependent on weapon skills for damage and had a stamina morph for whip or something even though they gave us poison claw and noxious breath. To give you an idea of what sets to use on a stam dk, my endgame pvp will be 5pc hundings rage, 1 kena, 2 leki, 3 agility with 5 inpenetrable traits and the rest divines. I am also going to experiment with 5pc black rose instead of Hundings to see how it turns out. Most people endgame use 5 hundings, 1 kena, 1 bloodspawn, and maelstrom bow and maul/greatsword. I am on XB1, NA, AD If you are as well and need help let me know.