Keep smart for a while. Avenging is, well... Almost useless, TBQH. At least at the pre-90 levels.
I heard it got better at 90+ especially since at that level Smart Cubic will barely stun anything, but I've never had it (so far) remove a debuff from me and it barely roots anything (even then only for like 1.5 seconds or something like that). Haven't noticed it take a buff off of anyone, either.