We recently stayed four five nights at Casa Milo's and couldn't recommend it more highly. In fact it's easily one of our best AirBnB experiences ever.
The Casa is a series of four apartments, two per floor. On the ground floor is the namesake restaurant, where were were served fresh, hot, complementary breakfast daily. Our apartment (apt C), on the top floor was a large studio with sufficient sleeping and sitting space, and a very modern and well furnished kitchenette. Though ours was the smallest of the four options, it was the only one with a large outdoor terrace. But the crowning glory was the floor-to-ceiling windows, which opened up to give the sense you were living outdoors in nature. And if things couldn't get nicer, there are black shades (controlled electronically) to block the morning light for sleeping. There is some noise (given the restaurant downstairs), which we did not find problematic. But we were also there during New Year's when the city was much quieter than usual. The king size bed was very comfy but the frame in this particular unit is very close to the floor so you may consider a different unit if getting up from a low frame is an issue for you. For us, the terrace and windows made up for that.
The location is also ideal. Situated on Avenida Amsterdam, one of the most charming streets in all of the city, it is a minute away from the park, and a quick walk to most of Condesa and Roma.
Finally, it is the people that make places special. Florenzia, the host who works with Alejandra, was extremely helpful and available. The housekeepers, Julia and Candi did our laundry for us (for a small fee) and couldn't have been more gracious and kind. Also, Israel and all the restaurant staff were great. Having complementary breakfast as part of the experience was a treat.
Given all these positives, I wouldn't hesitate in booking any of the Casa Milos units if you're visiting Mexico City.