Furygeddon Merc weapon: Conviction or Concentration?

I'm still very new, been playing the game just over a week. I've been running an insight pole on my merc but I don't really have mana issues anymore so I want to upgrade to either a Conviction of Concentration Cryptic axe on my merc. I'm leaning towards Concentration since it seems to have the greater overall damage boost but the Conviction (while not being high enough to break immunities, I don't think?) would be more of a help against PI's since it'll boost the damage of my Armageddon and my proc damage.

So I'm asking for the help of more experienced players to help me make this decision.

My character/gear currently:

level 75

20 WW

20 Lycan

20 Fury

7 Amageddon (will max out and put remaining points, 15 I think, into Firestorm to share damage synergy with my Fissure and Firestorm procs and my Armageddon skill as I continue to level up to 99)

1 Grizzly

1 Oak Sage

(associated pre-reqs not listed)

Ethereal Earth Shifter

Fortitude SacredArmor

Jalal's w/Um

Gore Rider's

Lava Gout

Verdungo's

Raven Frost

Bul Kathos

Mara's

16/20 Druid Hellfire

Obviously, from my build, you can see I rely more on Fury than Armageddon and always will. I use Armageddon constantly but it's more to help me deal damage to large groups of mobs and to help with PI's. A pure Fury build that swaps to Famine would probably be better but my build is fun and I really don't want to change it. I'm planning on a pure fury build after this one is completed.|||Since your armageddon is more of a support skill I'd suggest pride.

I had a similar build but I only put 1 point into each shapeshifter skill and maxed out armageddons damage. For that setup I used infinity.