Sorry for butting into your argument, but I don't think the topic is relevant anymore. We're actually discussing the second tier here. Although, I would like to correct something: Furies won't die from dragons before they get a chance to move, simply because they move first. The initiative difference is 2, and no Winged Horror can help with that. However, Megeras have the same initiative, so it depends on luck. And I think the question has already been resolved. Furies are the most useful second-tier unit (among melee units; comparing them to ranged units is not appropriate), followed by (in my opinion) Dancers (especially after the second upgrade, they are beasts), then Gargoyles, and finally the slowest ones, like Zombies and Demons, which I don't know how to rank. I didn't include ranged units in the calculation; I tried to evaluate them objectively.
Besides, if you consider Alt-Demons, they can cause a lot of trouble for the enemy with their ability, and therefore bring at least some benefit. IMHO, they are more useful than Zombies.
Among ranged units, the best are, well, Archers. I don't think there should be any disagreements or arguments about that. ;)