I had a lovely longterm stay at Isabel's. If you want to stay away from the more commercial areas of Lisbon and closer to less trodden (by traveler) local restaurants and bars then Isabel's place is at a great location, yet still very convenient to get anywhere typical within Lisbon. The metro is around the corner and so are bolt bikes and scooters.
My favorite aspects were enough room to host a visitor, work from home and have a separate place for sleeping and dining/living, having weekly cleaning services, and having a balcony on either side of the apartment—one great for people-watching, and then other for reading at sunset.
Lastly, Isabel and Miguel were kind, patient people—who supported me when I had a health emergency and also sent regular suggestions for visiting spots around the city. It always feels better to support kind hosts!