Polanco has grown by leaps and bounds. Once but a neighborhood of some five modest sections, today it also includes good parts of Grenada and "Ampliacion Grenada," too. Add to that a few neighborhoods of historical significance like Anzures, Veronica Anzures, and the whole collection of interesting little neighborhoods to the north of Av. Río San Joaquín, and you get a very dynamic city within the City.
Polanco seems to be enjoying the slight eclipse it's received at the hands of La Condesa which snatched away the crown of "most affluent" neighborhood in the city. Polanco has always been more modest, even granted it's considerable affluence.
For international visitors, even those staying in La Condesa, Polanco is still attractive for a few of its really good museums, and for the rather formidable shopping district along Avenida Presidente Masaryk.
That in addition to a considerable number of enclave-like smaller neighborhoods where exceptional meals are served, seven days a week.