We stayed for 3 nights in Ana's apartment at the beginning of June. It was a quick taxi journey from the airport (20 EUR), and Ana's husband welcomed us at the apartment. He provided a whole range of information about the place, what to do, where to go... It helped us feel at home straight away! The apartment is very nice and very comfortable. The location is perfect: close to public transports and a lot of great areas, but quiet enough and safe at night. We alternated between walks around Alfama and all the way to the castle, and taking the metro to other areas (TimeOut market, Belem, main square). I would definitely stay again.
Things I discovered during our stay:
1) The second bedroom is tucked between the living room and the other bedroom, and it has skylight-type windows with no curtains. Bring an eye mask if you need darkness to sleep.
2) Lisbon is hilly... I was glad I had a good pair of walking shoes because you're always climbing up and down really steep streets.
3) If you need to store your luggage, you have lockers inside the Santa Apolonia train station which is only a few minutes away, as well as a secure locker service in the street next to the station.