"We stayed here five nights and loved it, five stars at this low price. I will give the good and bad in case you have different priorities.
Concierge 5+: I stayed at 5-star hotels when I travelled for business and never had a more helpful and friendly staff. Just the best.
Transportation 5: Lisbon has a great modern subway, less than 2 euros a trip, and you are across the street from one of the hubs. Gets you to the aquarium/stadium, Alfama, airport, etc. fast and no fuss. Belem is not on the subway but easy.
Neighbourhood 4: Not bad. A good cheap fish restaurant 2 minutes away, tons of restaurants and shops on Avenida Duque d'Avila, two great parks and a fine arts museum 15 minutes on foot.
Breakfast 4.5: Great. All you can eat in a 4-hour window, coffee and snacks available all day. But if you are there at rush hour it's a little crowded.
Stairs 3: If there is an elevator I did not see it. My wife and I are healthy seniors who travel light, so we carried our own bags up two flights. You might be up 4 flights.
Amenities 4: Shared TV/game room and sun room for 6 rooms. You might meet new friends there.
Bathrooms 3: Good bathrooms but shared. 2 showers and 3 toilets for six rooms so we never had to wait.
Noise 2: We faced the main avenue and heard motorcycles until past midnight. Closing the wooden shutters helped a lot. You will also hear if the people upstairs decide to dance.
Did I mention the price? This place is a bargain."