Originally Posted by ILovetheReds

Depends on how much you would fly on AA.

If you can fly enough to be EP on AA and AA services the routes you want to fly as conveniently as Delta, IMO it's a no brainer go with AA. AA's international upgrade policy is a lot better, they only upgrade EP's for free so sometimes you have a seat empty beside you in First, you get free upgrades JFK/LAX if you take that route and if you don't get upgraded you get a free drink and sandwich at least.

If you are barely flying 75K miles a year and not enough to reach EP on American, Delta is probably your best bet. You still stand a decent chance of getting upgraded on most Delta routes (which you won't get free upgrades as a plat or gold on AA, you have to use the stickers and I know it's after all EP's have cleared and I believe you have to wait until the gate). You can also upgrade a non-status companion on American and they will clear a lot easier than on Delta.

If I wasn't a Delta hub captive, I would be flying American almost all the time.

Only issue is what will happen post merger of the programs. In airline mergers it seems like there are never any winners for either frequent flyer program. They usually say they want to consolidate the benefits to make them uniform and for individual benefits they chose the worst of the two.