Corpus is basically the tactical guys, can't be 1 shot, got so many options to protect their units, the works.
Sentinels are the pvp meta faction. High health, high damage, can't be shocked, confused, concussed, turncoated, etc
Aaand survivors are basically that faction that goes yolo xD
For every unit killed and/or lost their warlust increases which increases their damage up to 100%