Well, it's the first time we have a negative experience with airbnb. Pedro was super nice, and he welcomed us personnally during check-in, communication was smooth. So nothing to say about the owner really. The apartment is nice, however, the heating system lacked power. It took about 24h to heat the place up (we were there in January- probably not an issue during summer time). Also, the water took a very long time to warm up as well, we had to leave the water faucet on in the kitchen in order to have hot water in the shower, such a waste of water. And it seems like there's a gas leak in the water heater whenever the shower is being used.
We didn't like the neighborhood, clearly not the place you want to have a walk at night, even less spend your holidays at. It's located in the "transition" area in between Belem and Estrela (which are two nice neighborhoods). The place is a bit remote, but you can access it by bus or tram. Also there is a lightpost right in front of the bedroom's window, and no actual blinders but just a thick curtain...so it's like day during the night in the bedroom.
However, the worst for us was the noise. The apartment is located right on the final axis for airplanes landing in Lisboa international airport. Lots of cars up to 3am in the small street also make the place very noisy. Maybe the worst were the upstairs neighbors. People kept walking around with what seemed to be high heels very late at night (up to 4am) for the two days we stayed there. It was just impossible to sleep.
Overall, this place is practical for a very short stay and if a car garage is needed.