Me and the missus have just started a duo of a Fire/Dark Corr (me) and a Fire/Dark Brute, we may only be lower lvls at the mo....but boy, the AoE damage is going to be insane 
For my /Dark brute I gained the most teaming with an Ice corr. Resistance + Defence is a very good combo, and Frost Works meant that Dark Regen recharged before my increased hit points got too low.
My /Fire Duos with a /Thermal and with Healing Flames its good to just have the stacked Res and more heals. I think either brute would work with either cor, but most of the time I'd rather have good defence and good resistance over amazing resistance.
Amazing defence is another thing and should always be saught
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
For me i dont leave home unless i have 7 cors on my team, and that works well as most nights i have 7 cors holding my coat 
7 cors? You herding GMs?
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
I wouldnt mind teaming with a dominator, my brutes are more or less essentially made to aid them but I usually find the ppl i team with mainly have mms or corrupters etc.
He will honor his words; he will definitely carry out his actions. What he promises he will fulfill. He does not care about his bodily self, putting his life and death aside to come forward for another's troubled besiegement. He does not boast about his ability, or shamelessly extol his own virtues. - Sima Qian.
Best team I was ever on (fun wise at least) was 5 Brutes and 3 Dominators. Everyone wanted to keep moving to build fury/domination and it was a constant chain of destruction
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
depends on the brutes secondary, for example /energy brute would be best with an ice corr, but a elec brute wud be best with a thermal to stack res or def