On the desirability of AA miles vs others, a WSJ article discussing AA's performance
This isn’t the first time the airline has struggled with on-time arrivals and cancellations compared with competitors. In the annual Middle Seat
scorecard of airline operational performance,
American has ranked last or next-to-last in 10 of the past 11 years.
Subscription required, but here is a link to the full article.
WSJ - AA
But even with poor performance, it's hard to argue with free.