Great location, you are pretty much close to everything. I just fully realized it, on our last day. The apartment is very cute. You have a view of Lisbon and it invites you to actually stay in, have a glass of wine a good chat and just... be. The fact that the doors work with a code, makes it easier as there is no need of sharing a key.
The hosts were available and responded any questions pretty quick.
I would only be mindful of the stairs. The steps are very narrow and high. Typical of Lisbon, it might not be for everyone. We were on the top floor.
If you are looking for an authentic Lisbon experience, getting lost in its little streets--this is the place to be.