I travelled with my 14 and 15 year old teenagers and was satisfied with our experience. This place is very clean and the host is exceptional. Dima is polite, shows up on time and is very accomodating. We had a positive stay at the apartment and we were comfortable.
The guest needs to understand this is an apartment - not a hotel. There is no air conditioning, but there were fans and we were there on several hot days in August. Evening temperatures were cooler and the windows were open. However, you are on a busy street so be prepared for street traffic noise. I closed the windows, left the fan on and the street noise could not be heard.
Also, you enter the place through a typical European entrance into a small courtyard. It was different, but it was not a problem .
As far as safety, I felt very comfortable with the apartment and location.
The location is accessible to the tourist attractions - only 500 feet from the National Museum.
One piece of advice is keep Dima informed of your arrival time. I did not and I had to call him. However, once I called, he came over within five minutes. He showed us how the locks and lights worked and gave us a brief tour of the apartment.
In summary, it was a positive experience.