The location of the flat is very convenient but please be aware this flat is in the middle of Barrio Alto which is one of the busiest areas in Lisbon at night (full of nice bars and restaurants). If you're travelling with friends and want a bit of fun then it's a good choice, if you want something more relaxing and/or travelling with children I wouldn't advise to stay there.
Please, be aware that by the time we stayed there, the mattresses were extremely uncomfortable. They were really soft and you could feel every single spring on them.
Overall, the flat is nice and cozy and we never had any issue with hot water when showering 4 people in a row.