Overall I think this was a great option for a long-term stay. It's in a great location for easy access to museums, restaurants, shops, the Zócalo and metro stations in case you want to get around by public transit. It's also walking distance from a couple of grocery stores. It's located directly across from the park, which was a great place to walk, sit and read, or go see street performers. The area is always busy, which helped me feel safe arriving back at any hour of the evening and the security officers are pleasant and helpful. The host is also very friendly and accessible via chat.
I found that the place was well-equipped for cooking so I didn't have to order in all the time, but it was also within range of a lot of great places for delivery, including grocery stores. Despite not having a view, the place gets a lot of light which is always good. I worked from this location for the majority of my stay and I found that the wi-fi was good enough for streaming, working, and one-on-one video calls but struggled with larger calls.
If there was an AC/heating unit, I didn't find it but I generally found the temperature to be comfortable during the day. However, during my stay in the month of November, it got hot enough to break a small sweat in the afternoons if you left the shades open but at night it got very cold, which I was not prepared for. Come prepared if you are sensitive to cold. Also, given that the area is very busy, if you're sensitive to noise, you may not like it but if you've lived in a major city it shouldn't be much different.
Tl;dr: I felt safe and comfortable during my stay and I would recommend this Airbnb.