A group of 9 of us stayed here for a hen weekend, sleeping 3 to a room. It was the perfect base for us. Joāo helped arranged a transfer from and to the airport for us, and his friend David met us at the apartment for check in. There was a bottle of port waiting for us, and David also recommended some restaurants and bars for us (which were great recommendations!)
The apartment's well located within walking distance of the main nightlife areas (Bairro Alto, and around the Pink Street), although be warned that there are some very steep hills with slippy stone to navigate. So you may be better getting cabs to the main areas, but they're only about €6 so quite cheap, or I believe it's also well located for public transport.
There's also a small supermarket right below the apartment, and a pharmacy down the road, so it's well-located for buying food and bits for the apartment.
Joāo's communication was also great, from start to finish.
All in all, a great little apartment for a group, and Lisbon itself was just perfect!