We had a great stay at the appartment of Miguel. It's not big, but the space has been used to the most and for a family like ours (with 3 teenage daughters), it was more comfortable than hotelrooms. Me and my husband slept on the sofabed, which was surprisingly comfortable, I slept very well.
Miguels dad welcomed us to the appartment and gave us some information about the surroundings. The bottle of Port that was waiting for us as a welcome-gift was a very nice gesture and it tasted great! (Thanks again.)
The appartment had everything we needed (the two bathrooms were a luxury!) and everything was very clean.
There is a supermarket nearby (go right when you leave the appartment and then down the stairs, a few stairs down you find the Pingu Doce on the corner) and it is close to 2 metro-stations (Rossio and Baixa-Chiado).
We did a lot by foot since the appartment is located very central in the city, both close to the Bairros Baixa and Alto. It is also very close to the Rossio station, from where you can take a train to Sintra.
I would definitely recommend this appartment to anyone staying in Lisbon.