The only Stuns working are "Backhand" ( 21 points in Immortal spec ) , "Force Choke" ( 21 points in Immortal you can get it to work without channel-time ! ) and "Crash" ( 2s stun on Force Charge ) which is also located in the Immortal tree. You get a 6s AoE Mez called "intimidating roar" in later levels ( regardless of your spec ). I personally feel that if your grouping with a good MDPS, Immortal Spec would be the way to go since you can use CC on targets and protect them really well. Vengeance/Rage is good for having big Crits with full Gear ( i personally dont think an endgame-geared Juggernaut on DPS-Spec not in Soresu-form will survive any sort of serious DPS ). I just recently hit 50, so i dont have the best gear and have still not decided which PvP-Set to buy. Maybe combining two 2piece-bonusss will be a good way to go ( since you can switch out Mods maybe you can gear offensive with defensive setpieces !? ).