Our group of 7 wanted to experience Lisbon and live like locals in historic Alfama area, and Antonio's place worked great for us. We stayed in December 2016 for 3 days after Christmas Day. The apartment is in Alfama, you have a great view of the river from the living room and the upstairs loft is huge with 3 beds in it as well a small single room. On the main floor are two bedrooms and kitchen.
The building is quiet, and we didn't see a single person on the 4 flights of stairs (which we went up and down 2-3 times a day). However there are people there as evidenced by the smell of fish cooking every day when you are in the stairwell.
The building is in the heritage area, and doesn't have an elevator so if you are not fond of stairs, then this place may not be for you, although we got used to it pretty quickly.
Antonio received us at the metro station which is about 5 minutes walk away, and also helped with our luggage. He had communicated with us about our interests a few days before we arrived and had even printed out info on how to get to some of the attractions and also gave us tips on where to listen to Fado music. Note that most Fado places in the area charge for entrance.
From the apartment, the entire Alfama area is easily explorable, and the castle is nice at sunset. Walking to the touristic area in Lisbon center is easy and took 15 minutes only. Public transport is easily available too.
Families like ours or groups up to 7 or 8 will enjoy Antonio's place. We had a great time.