I stayed over a month at Karla's place in Cuauhtemoc and my stay there was just perfect!
The apartment is located on a quiet street yet only a couple of blocks away from countless coffee shops, bars, restaurants. Cuauhtemoc is the perfect location where to live if you want to explore the city by foot - Condesa, Roma, Polanco, Centro Historico, Bosque Chapultepec, etc. are all nearby.
The kitchen is super well-equipped and all appliances are of very good quality, the wifi works great, it's quite spacious, etc.
I'd definitely stay there again.