This is only the second major delay I have had on AC. About three years ago I was bumped off my flight from LHR to YHZ and pu ton a flight eight hours later. I got an upgrade and a refund: the offered me the cash amount for my flight or double the amount in the form of a voucher. I grabbed the voucher and used it for a Christmas flight.
I don't expect that for this Beijing issue, but its amazing that AC in there own home country failed to give just compensation. What's the point of being loyal to an Airline and their flyer program if they fail to act on it.
US Airways and United tend to be cheaper in the long run, and United adds up your total miles over your lifetime. I may just cash out my miles and switch to them.