Honu --
AA is miles-wise the most expensive program overall among the US carrires. Domestic UG on UA is 20k RT, while AA wants 30k.
However, as far as I know, AA is the only carrier to *add* a benefit in the last year. They made domestic Y/B fares a comp-upgrade for EXP's. Of course, that just helps make up for the lack of the UA HK49 certs.