This apartment is as beautiful and spacious as it appears. We didn't get great use out of the courtyard because the weather was pretty cold and wet when we were there, but it is truly gorgeous and would be so perfect in warmer weather.
Santos is a great, less obvious neighbourhood with lots of great restaurants and a great little cafe in Heim (right around the corner from the apartment). There is also a great little row of shops just next to Heim, with a great little supermarket where we were delighted with the quality of food we were able to buy. Having said that, it is also a very easy, short walk into Bairro Alto and Chiado to check out the better known hangouts.
All our dealings with the Gem staff were also lovely and helpful. Definitely recommend!