We stayed 3 nights in David's flat and we had a really great time. It is located in one of the most popular borough of Lisbon concerning nightlife and even a metro station and a supermarket are very close. You only need two minutes to walk for a great viewing point that offers a view over the whole city including the river Tejo.
The flat itself is in very quite area even if the borough is up all night.
It is very stylish furnished. I'd like to mention that there are a lot of little sheets on the walls that make you laugh about. There is a comfortable living room and a fully equipped kitchen with great view from its window.
David is a nice guy that will give you many useful advices for your stay and is very kind.
All in all I really recommend this flat!
I will definitely come back!