Warrenlm: You are correct. UA provides the 25%/100% elite-level mileage bonus only on UA-operated flights (and a few LH ... I always forget which). With AA, you earn this elite-level mileage bonus on ANY oneworld carrier. It's why I always choose oneworld carriers on routes that UA doesn't serve (for example, BKK-SYD is flown by TG, BA, and QF .. BA and QF earn me twice the miles as TG). It also makes it easier for me to justify flying high-quality carriers to Australia (QF) or to Asia (CX)!

BA Exec Club gives the elite-level mileage bonus only on BA and a few, but not all, other oneworld carriers.