The apartment itself is lovely, really comfy and clean. The location in proximity to Lisbon as a city is incredible. We found it easy to get to the various sites of the city and to navigate to and from the airport. You get used to the hill very quickly and would recommend walking from the Martim Moniz side as it's less steep and feels safer and cleaner.
However, the only downside of our stay and we realise this can't be controlled but feel compelled to note, there was a homeless person outside of the apartment for the entirety of our stay. There weren't any issues with the person, but they were quite noisy which didn't facilitate the most relaxing environment at times.