Edwin's studio in La Ciudadela is a great spot situated in new construction atop a historic building. Rooftop terraces, light, views are all fantastic, and I loved the neighborhood. 5-10 minutes walk away, across Bucareli, are some great parts of Juarez, which is richer in services and restaurants. 20 minutes' in the other direction to Bellas Artes or Zocaló. Also the superb public indoor market of San Juan Ernesto Pugibet.
One downside: be aware of the noise. The famous Plaza de Danzón is across the street, and it can be loud on evenings and weekend afternoons, with hundreds of folks ballroom dancing to live or very amplified music. OTOH great charm and "color" but at the very least bring good earplugs. And be aware that this is a separate room in a larger apartment - with its own entry but also a connecting internal door. If anyone is present "next door," you'll be aware of them and vice versa.
And a lot of stairs, if that matters to you. But ultra-charming. Worked for me!