. . . out of the mouths of babes

Can't help you on the upgrading with miles but I am sure a oneworld member can.

I guess that is our point though. It is important to investigate what a higher tier might do for you. If you are a casual traveller then you are probably doing the right thing. If you plan on travelling lots, the benefits of becoming a top tier member are worth finding out about. Those system wide upgrades are some of the perqs of top tier membership.

On UA you get 6 system wides for flying 100k status miles in the previous year.

On AC you get 8 for 100k status miles plus you get 2 more for each 10k status miles flown. Plus you get free access to all Star Alliance Gold lounges worldwide.

Want to cut the high cost of business class travel? That's one way to do so. But you really have to fly a significant amount to make it worth your time and money.

My mom always told me to join a frequent flyer program but I didn't listen. The only thing I regret now is not joining sooner and not concentrating all my miles in one plan sooner. I have been top tier for 4 years now and it has meant 100% upgrade success on all flights on my carrier of choice (AC), free lounge access, free weekend car rentals, free arrivals lounge access, almost instant access to the airlines reservations and reward program people, no blackout dates on rewards, mandatory provision of reward seats in all classes even when no reward seats exist (provided flights are not oversold) and the list goes on . . .