The apartment is perfectly located in a nice and quiet street in Principe Real (definitely our favorite area) and very close to other neighborhoods like Bairo Alto and the riverside. It's a very good base for your stay on Lisbon.
The lovely old town house apartment is clean, very spacious and cool, together with the garden it's refreshing in the hot summer. Their is absolutely nothing wrong with the apartment. And most important, we had good nights of sleep (quite new IKEA beds with (basic) spring mattresses). The only minor downsides are the little bit outdated kitchen (although Lisbon has very good restaurants and we enjoyed dinners outside) and the apartment can be somewhat humid (ventilating the house before going to bed and keeping the bedroom door a little open solved this minor issue).
A very nice extra is a portable 4G modem which you can take with you throughout the city to give access to internet when needed!
We would definitely recommend the Principe Real Garden Apartment and book this place again when visiting Lisbon!