In general we were satisfied with our stay at Maria's place. The best thing about it is definitely the location. It is right in the historic center and close to most things you would want to visit in Lisbon. We had no need for public transport since everything was within walking distance. Communication with the host was good, Maria responded quickly to our messages.
One thing that was not ideal was the bathroom which had a bit of an unpleasant smell.
At the time when we visited (early March) the apartment was a bit cold, but the host did provide enough extra blankets. There is also AC to warm up, but the one in the living room didn't work properly.
Aside from those few things, we were happy with our stay. We were there touristically but also working remotely, and the apartment was spacious enough for us all to work comfortably.