While AA is no longer the best, a $500 roundtrip copay off the lowest fares is likely to beat several carriers such as NW and DL where the required fare is in most cases going to be more than $500 above what you'd otherwise pay to sit in the plane.

I really don't like AA's move. I wish, if they had to change things, they'd have just implemented a new tier of mileage award... maybe double the miles instead of more money, at least as an option (though in most cases this would be a poor use of AA miles at least the pure mileage option would exist).

I find UA to be pretty good, though mileage upgrades do require buying an "H" fare or higher internationally. Lots of times my flights are only available in H to begin with given the destination and time of year I find myself flying so I'm not really paying more. But YMMV, especially as H is one of the higher economy buckets.

Want liberal upgrades? Check out MX. All fares are upgradeable, on a complimentary basis, for their gold members. Upgrades are confirmed 7 days in advance of flight and there's no special upgrade inventory. Upgrades come out of discount business (D).