For me AA is a no brainier. The reason I didn't do it before was because I didn't want to pay the initial price achieving top tier status with another airline. But now there is no reason to stay with AC.
I mostly fly to Asia and South America.
You do a platinum status challenge for $200 to have the priority baggage and boarding etc. while you reach your Exec status.
Then you buy 3-4 business class trips on AA, CX or BA to Asia. Paid business will soon put you at 100k through Elite qualifying points instead of miles.
Given that AC has almost completely eliminated upgrades for 2015 , I would have had to spend that money now anyways. Except now I will receive the real international experience on CX for example.
After I've reached Exec. Platinum I will receive 8 one-way upgrades to Asia and not to mention complimentary upgrades within North America.


So AC, please give us the eupgrades back as it was so we won't have to go through this hassle.
If you keep the eupgrades the way it was you will have many SE giving you business. If you don't , those who can leave, will!
But I know I'm dreaming......