Resurrect? or Salavge?

[Spoiler]

The decision is two-fold: do you commit to resurrection infrastructure, and only then do you ask whether to resurrect.

ZK is a game about extracting more effective metal from the game-state than your opponent, which makes resurrection look good. But it's easy to forget that the units that are dying are more likely to be obsolete than the units that you want to be making. If the map is all choked up, even if resurrecting a glaive seems like a bargain, the unit is next to useless and you'd be better off eating it and contributing the 20 or so metal to your krow.

It's also the case that morphing your commander is an enormous investment, and it's usually bad when you're committing to a reactive game-plan (such as mech-jesus) that doesn't have a more immediate effect on game-state. Even athena which is only 500 and comes with 7.5 resurrection BP, is better used for the units it can make and bonus radar jamming than the resurrection plan.

[Spoiler]
Resurrection requires 200% of the units value in energy, but returns 100% of its metal value. Reclaiming and building a unit from scratch only costs 100% of the energy, but returns 40% of the metal value.

In other words, resurrection is more efficient once you have access to high amounts of energy and a lack of metal. Early to mid game you'll occasionally be running pretty low on energy - that's when reclaim can be more resource efficient.

(see modrules.lua and the modrules doc)

I haven't found any clear explanation for buildpower cost modifiers. The eco wiki page has walls of text, but is completely useless as was to be expected. Anyway, I would assume that build cost for both reclaim and resurrection is 100% of the return value. If that's true, then resurrection is more buildpower efficient at 100% the original value while reclaiming and rebuilding would increase the buildpower investment to 140%.

Worth noting: Repairing units is even more energy efficient (50% of original value). Repair buildpower costs are some random multipliers that I cba to remember, but they double or quadruple or such while the target recently took damage.

Which is why it may be better.
But still, salvaging an ultimatum looksfun

Meant to say: Revive
Salvage is less useful if your reaching max metal.
Ressurect can save armies from destruction/get units you want.
Repair just works