Critical

What is better? Critical Strike Damage, Critical Strike Chance, or Critical Strike Multiplier?

I would think that the multiplier would be better, maybe chance if you have a ton of it but that's just me. Anyone have some solid guidance on this?

well it depends on your build :)

There are two critical strike properties in the game: critical strike chance and critical strike multiplier. The first is based on the weapon or spell you're using (5% base in most cases) and is the chance that an attack will be a crit, while the second is 150% by default for all characters which means your crits will do 1.5 times their normal damage. When you build for Increased Critical Strike Chance or Increased Critical Strike Multiplier, all such bonuses are added together, and the base crit chance or crit multiplier are then multiplied by their sum.

So for example if you have a dagger with a base crit chance of 6%, a +20% Increased Critical Strike Chance and a +40% Increased Critical Strike Chance passive node as well as the Increased Critical Strikes support gem linked to the skill you're using which adds another 70% Increased Critical Strike Chance, your total critical strike chance will be (1 + 0.2 + 0.4 + 0.7) * 6% = 13.8%. The same math also applies to the critical strike multiplier.

In any case, you should only build for these two stats once you already have enough increased damage bonuses. Up to a certain point, increased damage gives you much better returns, and only after you reach that point you get better returns from criticals. When you do start building for them, build for both of those stats at the same time. To get the exact optimization for your build, you'll have to do the math yourself.