First- My main interest in posting on this thread was to agree how easy, cheap, and convenient public transport is in BA, and how much you learn by walking as well.
But the argument of US versus Argentine prices is one we have had here many times.
I have been living in both places for almost 12 years now. I know exactly what the cost differences are between Washington State and CABA. And I can say that my cost of living, for the same or better quality life, is much less in Buenos Aires, and has been every year for the last 12. YMMV.