My partner and I spent one night in Maria's cozy 4th floor apartment. The space was as advertised, right in the bairro alto (bar/party) neighbourhood. We had stayed in the area previously, and had no trouble locating the place. The bed was incredibly comfortable... possibly the most comfortable of our entire trip to portugal! Maria was a very accommodating host, even when we arrived later than expected. As with many Airbnb's, she requests you message her prior to arrival, which was challenging for my boyfriend and I who were relying on free wifi hotspots. Luckily the bar right next door was very helpful!
The apartment is a cozy space, compact and nicely furnished. The kitchen and bathroom are small, but certainly functional. The fan and windows on opposite sides of the space kept us comfortable even in mid August. As you are right in the middle of the bar/pub area, it is understandable that it is noisy until late at night (3AMish). We were both able to sleep well, regardless! As has been stated in other reviews, the small staircase and several flights of stairs to the apartment could be an issue for you, depending on your mobility (and height! my boyfriend had to duck the whole way!). That being said, we both had no real problems.
A convenient choice for our last night in Portugal before taking the metro to the airport.