We spent 6 nights, 5 days in Lisbon, in this apartment and it was exactly what we were hoping for. The welcome we received from Alex (on behalf of Isabel) was perfect. He was there to meet us, provided a very quick introduction to the apartment and then left us to ourselves to enjoy it. The apartment itself is great. Two good sized bedrooms both with ensuite and then a half bath in the hallway. The main living area is great, it has three big floor to ceiling windows that give a fantastic view over Lisbon and allow all the sun to flood in. We couldn't have asked for more in our first AirBnB rental. For us the location couldn't have been more perfect, 3 mins walk from the main Praça and 2 mins from the Sé. The Castell was a 10 min walk all up hill but easily doable especially if you stopped for lunch on the way up:). There are numerous places to eat in the area all of varying prices but all very good indeed. Getting around Lisbon is easy, the trams run frequently but are not cheap so I would recommend buying a pass.
There is a significant amount of construction/renovation going on all around the area so if you are expecting to sleep in, think again as the noise starts at 8am and continues all day. There is absolutely nothing that can be done about it but be warned that your daytime bliss will be broken.
Overall we were happy with out stay and will likely do it again.