And now I see that you are trying to Africa fly via Dubai to use awards earned from all of your work trips to Toronto. I misread that you were traveling Toronto to Africa regularly for work.

In that case, I think that you'll find that UA will require fewer miles and fewer surcharges in redemption. A quick look at the aeroplan chart looked like 150k plus fuel surcharges for AC vs 120k plus tax for UA redemptions in J to Africa from US roundtrip. I have used UA partners for award and paid tickets to Africa (SA, ET, TK, LH) but never on your proposed route through DXB. I collect and redeem on UA.

Best of luck, sounds like it will be an amazing holiday. Consider the UA changes for attaining *G status with a spend requirement for 2014 and see if that will factor into your AC vs UA consideration as well.