The most difficult alternative

For me, the most difficult choice is between Djinns and Nagas.
Djinns are definitely stronger, but they are more difficult to build and are more late-game units.
Nagas are cheap and tempo-based; if the map is small, I take them, and you can start fighting very actively right away.

Here, it's more the opposite; if the map is small, it's better to build Djinns, splitting them into 1+1+..., making it easy to clear the map. In the final, a few Djinns decide battles with magic, while a few Nagas look weak.

But there's one choice I still haven't decided on: Nomad/Harpy. I have an explanation for building all the other units (opponent, map size, resources, units in the area), but not for these.

Here, it's usually always Harpies. You build a tank, use Harpies to boost it, and quickly move to the opponent.

But here's what I've noticed. With similar stats, Tigers and Nomads (Tigers are even a little weaker) die too quickly in battle.

Yes, yes, yes!!! There is such a feeling. But Tigers have 35 health and 19 defense, while Nomads have 45 health and 13 defense. Multiplying, we get a defense of 665 for the Tiger and 585 for the Nomad. Here's the explanation. Tigers are 14% tougher than Nomads. Calculating damage-attack in the same way. We get that the Tiger's attack is +10% compared to the Nomad. Tigers are much better in terms of their stats. I'm more surprised why this pair has almost the same XP for killing them (53 and 52)!