I highly recommend this small flat. The location is perfect, in a tiny alley in the Alfama. The house and the apartment are refurbished, the neighbours were very quiet when we were there. The apartment overlooks rooftops and has lovely river views from two sides. We found just about everything we needed in the flat. It's very convenient for public transport to the various sightseeing spots (also to Sintra, Belem, and Cascais/Estoril), and there are some excellent bars and restaurants just a stone's throw from the house. Communication with the host and his representative in Lisbon was excellent, too.
The only negative to mention is the fridge, which was really noisy every time the motor came on. Since the flat is small and the kitchen is right outside the bedroom, there was no getting away from the noise. I'm guessing the fridge is old and needs to be replaced, and once that's done, the flat will be lovely and quiet. Until then, pack ear plugs!