These critters are hell on two clawed feet. One swipe from a Predator will just about kill a Nomad and two swipes will kill a lower level Stalker. A level 6+ Predator can sustain 2 direct hits from a marksman bow to give you some indication of their strength. This is why humans rarely research the marksman bow.
You can use this unit for just about anything, but at 4500 gold and any accompanying items you might want to use with it, the price tag for a fully loaded Predator can be steep. Hope for a very rich commander or make sure you are picking up any loot you earn to keep putting these on the field. Kill NPC for gold. They give gold and a melee orientated predator should have no problems with most of them. A predator has enough with Rabid or Carnivorous for keeping most enemies away from base. Legionnaires are more expensive to field cause they tend to use more items.