Roberto's place is exactly as described and there's not much to add to the other reviews here.
The apartment building is set on the edge of a lovely, leafy plaza, close to great coffee shops, restaurants and Glorieta de los Insurgentes, which has access to the Metro (Insurgentes, line 1). The apartment itself is tastefully decorated and has all the amenities needed for a comfortable stay.
Roberto was friendly and helpful, and check in was a breeze. He even left some local beers in the fridge for us!
If we find ourselves in CDMX again, we will be booking this place again.