It was a fine home base for our 6 days exploring Lisbon--the location is near public transit (tram just outside the door and several bus lines a block away by the Basílica da Estrela). Having an AC/heater helped with the humidity, and the shower was excellent. Wifi was quite good (200 Mbps download at the time I tested it). The kitchen was well enough equipped to have coffee and light meals.
A few things could have been better: the two pillows on the bed were very thin and lumpy. The kitchen items near the cooktop were greasy, including the electric kettle, and a few dishes we pulled out of the cabinet were dirty. The couch is small and had several stains on it--it wasn't ideal for lounging. Lastly, my partner was particularly bothered by the smell, which he described as a cat litter box (it didn't bother me, so I suppose it's just dependent on how sensitive you are to that sort of thing).
For the price of over $160/night in the off season, we didn't feel like it was a great value