Armor pen in pvp

Armor penetration AA in pvp, thoughts??

I use precise strikes on sin . because its a nice add-on to the normal penetration feat and you will still have more than enough crit damage rating

On other classes i dont see a reason to use it . Maxed out : you ignore like 4% armor , and around 1.5 % protection.
Better to stack debuffs

I use it on guard and bs because they have feats that it stacks up with and it works great. Guard sucks at debuffing so it helps a great deal (and also reckoning is affected by the spell penetration directly). Not too important on conq although you have so much crit rating you could just drop decisive and go pressing + precise. It hits hard.