We stayed for three nights in the apartment and enjoyed the location directly in the city very much. Most attractions are just a couple of minutes walk away and you are connected very good to the public transport system.
The noise level at night in the street of the apartment (between 10 PM and 3 AM) was some kind of annoying but we've read this issue already from other guests and so we were prepared. However, we were hoping that it won't be so noisy in winter time but it did. Nevertheless, Alexandra was supplying earplugs and we maybe should also have just joined the party people....
The apartment is well equipped and cosy so it's absolutely ok for a couple of nights. Please keep in mind the 4th floor without elevator and steep stairs. But no problem if you have a (small) backpack.
If you travel during winter then I advise to bring warm clothing since the individual thermal sensitivity could be challenging.
Overall, we loved Lissabon very much and can recommend Alexandra as a host.