Best Weapon Upgrades for a Hammer?

Just wondering what are the optimal Weapon Upgrades for a Hammer Build I should be aiming for.

I know 15% damage over 50 hp is a definate.

Then as for prefix:
I was wondering more damage and life leech with Vampiric 5 or Furious for 10% chance more adrenaline.

As for suffix:
Dunno, not many good things here. Fortitude or Defense but I was wondering if there was something more offensive.

Base it on your build - shocking haft if using conjure lightning, cruel for longer deep wound, etc. I like +armor for the suffix since I don't have a shield. If you want more offense then the 20% chance of hammer +1.

Well, there's no "Perfect" or "Best" upgrade for any weapon. It all depends on the situation and the best, is to have different weapon sets.

If you ask me, I'd get a Furious, a Zealous and a Elemental set. Don't get Sundering, it's not worth it.

Generally, here would be my suggestions:

Furious (+10% adren gain to chain combos faster)
Zealous (energy management, if you're having problems in that area)
Vampiric (+5 armor-ignoring damage per hit)
Elemental (for conjures and/or specific team builds like Spinal Shivers, Thunderclap, etc)

Defense (+5 armor, consistently reduces damage unlike +30hp)
Fortitude (+30hp, better against degen than +5 armor)
Shelter (+7 physical, easily the most common damage type)