We had a lovely stay in Diogo and Carlota's apartment. It is a perfect location- close to the lively district of Barrio Alta, Bica and easy access to public transport, but down a quieter street. It's off the main area and generally very quiet. However, make sure you bring ear plugs if you're staying on a Saturday night- is noisy then! It was perfectly quiet on Sunday night though. A 5 minute walk from the train station accessible from the airport.