dark knight or knight?

[shqiponja_hayabusa]

I am having this dilemma as I am to depart for the laybirinth which troop to take there. Since the slots are 7. Necro, Sa, Inq, Arch, Dryads, Knights, Hunters or Elfs.
So between Knights and Dark Knights? My leadership allows me to recruit 130 DK and only 112 K. I have Sa in my troops so they gain more morale because of the comander trait. But however I wanted to know which troop is better regardless though I know that is fairly relative.
(one thing, when comaparing the details, there is the attack number and there is a blue number in brackets next to the attack and defense, what that stands for?)