This is an amazing apartment. We stayed at Nai's place for just over two weeks, so we really got to know both the apartment and the neighbourhood. First of all, Nai was incredibly kind and welcoming - she gave us loads of advice on what to do, where to go, etc, provided a fantastic "welcome pack" for breakfast, and checked in with us (via WhatsApp) every now and then to make sure everything was OK.
The apartment is, to be honest, even better than the images on Airbnb....in particular, the living/dining area is huge, and the views are spectacular. We also took advantage of the balcony, which gets the sun until around 3pm - but also in the evening (it's a great place to sip a glass of wine whilst you look out over the city!). Other key things for us: the bed was very comfortable, the kitchen is well-equipped, and everything is very clean. Finally, having spent 15 days at the flat, we got to know the neighbourhood pretty well - Condesa is great (and Nai's place is just a couple of minutes' walk from some great cafes and restaurants. Roma is also lovely, and easily walkable.
Our advice is - if you are staying in Mexico City, try to stay as long as possible, and try to stay here!