i have used perserverance religously since the start of this expantion and loved it. Right now i have my zerker tree setup like
this.
I mostly do heroic zones with 1 healer and everytime i heal myself for 8-11% of the heals zonewide. Might not seem like much but i think it helps.
Another thing i really love from perserverance line is the hold rage AA. Getting rid of all the negetives on it is fucking sweet and if you put 5 points in the TSO tree your adding even more shield% on it which is super sweet considering the recast on it goes great to time in between useing adrenaline. Or just for normal tanking where you dont have to spam adrenaline this thing is huge "free" avoidance with no drawbacks.
But im starting to think i might change specs to debilitation line for raiding and use my normal spec for heroics. Because in raiding its different... Those little heals probly arent helping much and i guess upgradeing those mini debuffs from our CA's isnt too bad on raids cause there is 24 people on the mob instead of only 6.
My new raiding spec might look something like
this. (might switch around some points between weaponshield/juggernaught/bloodrage)
The only thing i really dont like about this new spec im thinking about is not being able to put AA's into Hold rage. I forget... how much does it debuff your haste/dps again?