Upgrading armor vs. weapons first?

[Hammy]

After consideration, as Zerg I always go for armor first. Not only does it benefit all of my ground units, but it allows my zerglings and (especially) banelings to reach melee while fighting. It's also great for roaches, especially versus the units it's supposed to counter.
The only time I go for +ranged is when I commit fully to hydra, but that's rarely a good idea...

[KadajSouba]

Well, I think that the very core of the game, is to deal more damage to your enemy than the damage you are taking. So I think that in general terms, damage upgrade is always better, because if you want to win, you have to destroy your enemy.

Of course as I said, this is a very general way of viewing it.

[Todie]

Why would you want to upgrade the armor for immortals?
The armor is counted before the hardened shields, so it's useless to research armor for immortals in most cases, and immortal is a high damage unit, so an damage upgrade pays of more.

i didnt know it was counted before hardened shield (are you sure?) but even so, shield 'grades on immortals are great becasue tehy make that hardned shield last longer, even when under stress from low-tier / low-dmg-per-attack units.

[Krikkitone]

Simple Rule:
Value of +Weapon depends on the units you are upgrading
Value of +Armor depends on the units Your Opponent is using

Generally +Weapon upgrades amount to somewhere between 7-20% boost in effectiveness

+Armor upgrades range from
20% boost v. Zerglings
down to
2% boost v. Thors

So if your opponent is using
Thors
Siege Tanks,
Colossi
Brood Lords
Roaches
Immortals
Dark Templars
Void Rays (and your units are Armored)
Vikings v. air
Marauders v. Armored
Hellions v. Light
Banelings
Or Psi storms, etc.

Then Armor << Weapons

But if your opponent is using a lot of
Zerglings
Marines
Zealots
BCs
Carriers
Mutalisks
Reapers

Then Armor >> Weapons

[Hammy]

Yes that's pretty much what I said in the last thread about armor vs weapons Krikkitone, and I still agree with it.
But the thing is, in game you have more control on what you're making than on what your opponent is making, and anyways all armies are mixed, so you can't always think like that imo.

You have to think more about how the upgrade is generally helping your gameplan (not your immediate army).
Here are some exampes that go against the basic reasonning:
-If you're making marines against muta: you should get damage, because the muta will melt if they attack you head on anyways, but with more damage you can pick them off when they get mis-microed. And he won't be confronting you directly anyways until it's over. And besides, you definitely need +damage anyways if you want to keep those blinglings away.

-When going bling/ling against a zealot heavy army (meaning not only zealots are fighting), it makes sense to get a quick +1damage since my banelings will take out the zealots easy anyways, and the extra armor would be worthless against the stalkers anyways. Zerglings might get owned by +1 zealots, but honestly zealots are no threat when you have banelings. The +1damage will be very helpful while taking down other tech units such as immortals and stalkers anyways.

-You put marines and marauders in opposite boxes, but they're actually always used together. How many marines should add up to a marauder? When fighting against M&M, I just get armor because it boosts my whole ground army and helps my army get into range.
Hell, +armor might also help set up a good concave in some scenarios. If ling/hydra is in play, the longer your zerglings survive the better surround your hydra will have because the M&M won't be positionning themselves while fighting your melee.

I'm just saying, this is true:

Simple Rule:
Value of +Weapon depends on the units you are upgrading
Value of +Armor depends on the units Your Opponent is using

but the upgrades you should be getting can't really be summed up so quickly.

I'll drop by tomorrow to elaborate more.