hey nw_traveler! i'm based in bos and travel a few times a year to china. must of my coworkers fly united with a mileageplus, but i decided to go with aeroplan. why? 1) my in-laws are in toronto, so with the miles i accrue, i can travel with my wife there on aeromiles. 2) i can get r/t tickets for as low as 15K miles to toronto, but the "fees" are high, about $150-200/ticket. 3) the threshold for *A gold status i 35K instead of 50K on united. that means i'll have free *A lounge access, along with other perks. i don't think i'l hit 50k, so using my united # won't get me to gold.

you should also think about how you plan on using your reward miles. i think it costs more aeroplan miles to travel exclusively in the US, so it's a bit hard for me to use miles when i just need to get somewhere here. i plan on saving them instead for longer trips to asia/europe, with a connection in yyz.

good luck!