We had a fantastic stay in Sandra's apartment. It was spotlessly clean, very spacious, and we loved the authentic charm of the building. The location could not be better, you are a 10 min walk from all of central Lisbon's sights. Sandra was very communicative and on hand for any questions we had.
The only tip I would give is that the key to open the door is unusual in that it is X-shaped, so you might need to try it from more than one angle before it fits. However this wasn't a problem once we learned how to use it. I can't recommend this apartment enough, it was perfect for what we needed :)