Thanks very much for providing this. I will have to look closer at the fare codes when booking- although it is odd because usually anything in Tango Plus falls within the "economy" fair codes and Tango within the "discount economy". When I bring up the flights on United.com they show as "o PQM's" but when I look up the same itinerary on Air Canada.com they show as "Tango Plus" and their is no Tango option available.

Just very frustrating as I do quite like flying Air Canada, especially the quality of the planes and service but for the miles I will be flying next year I will for sure hit 1k in United which will give a good chance of upgrades hopefully at least 50% of the time. Even with SuperElite on Air Canada the 70 eUpgrade credits will be gone in a flash- if you fly 6 or more 1500+ mile segments in a month there they are all gone right away. Its too bad Aeroplan wont adopt an upgrade policy like the American carriers, then their would be no question I would stick with them- esp since when I switch for next year I will be missing out on bonus mileage accrual.

To answer your earlier question, upgrades are most important for me. As my company only allows business class on flights over 5+ hrs it is rare that I get to snack a biz/first class seat that way. Also obviously bonus accrual is also great. Everything else except for the priority baggage is pretty much a wash for me as I carry a Plat Amex Corp card and Nexus so priority check in, security and lounge access isnt really a bonus.