Arcane VS Combat

Arcane Apprentices and Combat Mages are both equally used throughout the community, depending on how many mages you have.
For lots of mages, Arcane Apprentices is the way to go.
For a little amount of mages, Combat Mages are better.
So...
What is the dividing point?
I have three mages (Belthor, Philinus, Circe) and I use Combat because Circe's mages help Einar's AoE, Philinus' helps Azod, and Belthors' help William's and Edward's.