In general, I have had pretty good success with both AA and UA in redeeming awards. I don't think one example is representative of AA's general award availability, particularly an example involving relatively short notice travel to THE most popular award destination during peak vacation season. I could easily site personal examples on UA and other airlines where I attempted to reserve COACH tickets far in advance, to far less popular destinations, off-season and have had trouble.

I do agree with chazas that the statistics don't tell the whole story. They don't address particular routes, particular times of year, days of weeks, flights, etc., but in the absence of any better evidence, I continue to believe that AA has the best overall award availability of the major airlines with UA a close second.

I also agree that miles from programs like Diners and Starwood are far more valuable than miles stashed away in a single program.