Heavy Strike and/or Glacial Hammer?

Right now, I have both of these equipped, with different support gems. Thinking of swapping one of them out to get more variety, instead of having two things that are just "melee attack but better." Is it too redundant to have both? If so, which would you all advise keeping? Glacial Hammer does more total damage, but I'm worried about cold resistant monsters if I rely on it completely.

The difference is pure physical skill damage plus knockback versus cold elemental skill damage based on physical damage.

If you plan on grabbing passive nodes like Catalyze that increase elemental and weapon elemental damage you will eventually get Glacial Hammer to out-DPS Heavy Strike, even against cold-resistant foes. On top of that, Glacial Strike has that ever-useful chill-on-hit and chance to freeze targets. If elemental damage nodes are out of your reach or not within the scope of whatever you plan for your character, you may look to Heavy Strike.

Alternatively, you may build on that knockback with passives and higher physical DPS to a point where you can create time to regenerate your life between hits, assuming you're in a one-on-one situation with a boss such as Brutus. I'd suggest looking up the mechanics thread (http://www.pathofexile.com/forum/view-thread/11707) about how Stunning works. I can summarize that you will need to deal a lot of damage against a high-base-maximum-life foe in order to have a decent chance to stun them. I strongly suggest stacking on physical damage and grabbing knockback nodes in order to be able to buy time to regenerate your life even against ranged bosses by knocking them back some distance AND having a reasonable chance to stun. Emphasis must be made on improving your damage output, though, because foes can ignore stuns if your chance to stun is less than or equal to 25%. If you cannot reach this mark without turning into a glass cannon, Heavy Strike won't be as an effective choice as Glacial Hammer.

You can probably guess that the simpler choice would be Glacial Hammer based on how much I had to type to make Heavy Strike sound useful. I am assuming of course that you're using a Mace or Staff weapon anyways so the difference in weapon requirement isn't relevant.

Keep in mind that I am only speculating and would rather point you to whomever has actually had experience in this kind of decision.

If you run an Added Fire Support and the Hatred aura then Heavy Strike is probably the highest damage skill in the game, and way higher than Glacial Hammer.

If you dont run that support and aura then go with glacial hammer.

Edit to clarify:

Heavy Strike does 150% physical damage, +more per level of the skill. It can get up to about 200% total. Multiply that by a weapon with a lot of physical damage (IPD and plus interger physical) and you get a lot of physical damage. Then Added Fire Damage and Hatred add a percentage of your physical damage as fire/cold damage, and multiply that by weapon elelemtal damage bonuses (passives, gem, gear). The end result is that heavy strike hits harder if you have that gem and aura, because it scales much better with them.