I had a comfortable stay at Gulbenkian Park Residence! The room, bathrooms and kitchen were clean. The communication with Sven (owner) was easy.
The room is spacious, the twin beds are big and I had a good sleep. There is no view from the window, but the good part is that there is no noise from the street (although it is anyway a quite neighborhood). In terms of noise, the room is next to the bathrooms and kitchen- so it depends on the other guests how careful they are to not slam doors etc.
Tea and coffee are available in the kitchen, I appreciated this.
Although the apartment was fully booked (7 rooms), I never had to wait for the bathroom.
There are quite many nice cafes within 10-15 minutes from the apartment. There is enough public transport to reach any part of Lisbon and nearby towns/ places of interest. You can also have a very pleasant walk to the heart of Lisbon, through the park and wide avenue.