Myself and two friends spent a wonderful weekend in Lisbon at Joao's apartment. The apartment is located very centrally and close to bus / tram stops and the Cais de Sodre train station which makes it a great place to see the from. The flat itself is small but perfectly comfortable for three people, and has all the amenities you could need, including shampoo and conditioner in the bathroom which was a nice touch.
There are a number of shops within a few minutes walking distance, including a good sized supermarket on the street right behind the apartment. There is also a tram stop located on the same street where you can get on Tram 28 and travel up to Alfama very easily. Just down the road you can get on buses or trams to go to places like Belem, which is only about 20 minutes away and a beautiful place to spend the day. The apartment is also easy walking distance to the Time Out food market and Bairro Alto, which has great night life.
Joao is a very helpful host who was easy to communicate with before and during our stay. All in all, I would highly recommend this apartment for you stay in Lisbon!