Ninja's all stand at range when you really want them to melee and then run off and agro everything in the room.
Robots all do range and get stuck in lifts
Thugs all do ranged attacks sept for the arsonist who runs in and dies.
Mercs all do ranged sept the medic who always runs in first and dies leaving your other mercs with no heals.
Zombies all shuffle around slowly and do ranged attacks when you want them to melee sept for the grave knights who agro everything in the room.
Defiant's GoEH/MILITIS METUS
My arsonist never dies :P My arsonist can pretty much solo spawns ;P
Nooo, the thugs arsonist is a fricking aggro magnet because of his firebreath!
Look closely at the arsonist doing his firebreath, you see him holding a lighter while spitting the fire out, it's a great little touch!
I find the medic in the mercs is ALWAYS the first to die in any fight, I don't know why, maybe i should rename him Sgt. Suicide or something!
My arsonist is well protected. My enforcers, slotted for def, are very protective.
Zombies have highest survivability, thugs and robots have highest damage, others are gimps 
This is interesting. I haven't seen Primaries to look similar like MM primaries. You get 3-4 different kind of pets and Pet Upgrades. 2 Attacks. That's about it, mostly. But, what makes each primary different. Pets?
My question is. I want to know the charectaristics of each primary pets. From what i've read, I think I noticed that Ninjas deals the most melee-range damage? but they are fragile?
Robots don't get disoriented?
Undead have toxic resistance and lasts longer than ninjas?
Anyone can help me with each primary charecteristics, maybe I got this wrong.