It really depends on your perspective: a largely domestic traveller flies AA, while a largely global traveller flies OW. For me a big part of choosing UA over AA is that my UA club membership provides access to *A lounges, while my AC membership has far fewer reciprocal lounges (i.e. a couple OW lounges when on AA, and QF lounges when on QF). I oscillate between low and mid tier elite so this stuff matters to me.