Which of the Warlock creatures do you like the most?

I know that the damage increases non-linearly. But still. A stack of 10 Dryads deals about 20 damage to a Hive. This kills one Assassin or 4 unupgraded Goblins, while there are about 40-50 Goblins near the mine. It doesn't seem like they'll kill many. In my opinion, they are more useful in melee combat.