Generally I'm pretty happy with the upgrade rules -- with one BIG exception. I'm generally happy because I almost always fly on unrestricted fares. It's unusual for me to fly the same itinerary originally booked.

The only restricted tickets I ever buy are websavers. These are so cheap that there's not much to lose by throwing them away in the event of cancellation.

However, a couple of times I've been denied upgrades on websavers. I understand the rules completely, but I fail to see the sense in AC denying at-the-gate, standby upgrades to its best customers. For me, this policy cancels much of the goodwill that AC has built by its otherwise good customer treatment. For me, this policy makes the difference between being totally loyal and constantly considering a defection to another carrier.