Aside from the talent portion, MAO seemed less commercial to me and put more focus on scholarships (I volunteer on the local level). A woman needs to be matriculated somewhere and have a stellar academic record in order to be even considered as a prelim candidate (for us, anyway).

Miss USAs travel the country speaking on a number of issues (if they're smart enough). Miss Americas have a chosen platform.

It's a harsh generalization, but if I had to draw a comparison...Miss USAs=not too bright. Miss Americas=very educated.