We had a very nice stay in Lisbon. The apartment is essential but for us it was perfect. It is in a small pederstian street so it is silent. If you ask the taxi driver to take you to Calçada Sant'Ana you can avoid the stairs up to Rua de Martim Vaz. The only problem, was that there is no mirror in the bathroom, so I would suggest to put one somewhere.
The is 10-15 mins walk from Barrio Alto and Alfama. Nearby there are a lot of good small restaurants. I would recommend this place to stay.