Darth vader Post Knightfall is a lot worse than Knight Fall, knightfall was his true prime, but he lost a lot of mediclorians due to his severe injuries and blood loss, causing him to be way less powerful purely in the force and begin to lose his way, so he instead uses dark side knowledge which is much easier, originally he was a master at agility and speed, but he was completely nerfed due to his injuries, so he is not nearly as powerful.
1 cis (billions if not trillions of battle droids so come on) 2 Empire (its also gigantic even if its troops are not as skilled as the republic ones) 3 Republic(have the best soldgers) 4 Rebels or new republic(depends wich stage of the rebelion is meant) 5 first order(we dont know enough abeot the stenght but what we know is that it is far from beeing as strong as the empire) the sith are just so much older and are not an typical army as the other ones