I was traveling with my mom and I was more tolerating of the apartment and the area it was in then her. The apartment is located in a small street that is not easily accessible by car (unless you are used to driving in Lisbon). The area is not very fancy... But very safe and well located to visit the city :) the apartment is very dark, apart from the windows in the front door and the window in the back, there really is not much light. Anyone claustrophobic should not rent the apartment. The main bedroom is quite spacious but the second bedroom has no windows. The kitchen is very small and there is no kitchen table, you eat at the counter sitting on stools.... More than 2 people cannot fit at the counter.
The apartment is also very humid. When we were there and opened the back door to let the air in, the damp smell almost disappeared but when we got into the apartment from a day out, and the apartment had been closed all day, it smelled very badly of humidity. We only stayed 3 nights, I have asthma and with the level of humidity, it's a good thing we didn't stay longer, I don't know how my lungs might have reacted.
I think that the apartment wasn't completely finished when we were there so I am certain it will improve with time. All and all it is not bad, especially the fact that it is ground level... Lisbon is a city of hills and stairs and we were glad to not have to walk up 4 flights of stairs... I didn't mind the smallness and darkness as we were there to sleep and eat but my mother really didn't like it and also the fact that it doesn't have an emergency exit... But if you know what you are getting into, it's a great deal! Enjoy Lisbon!