This flat is in a great location — easy transfer to/from airport, everything you need in walking distance, and easy access to public transport. The flat itself is very well-stocked and beautifully decorated. The building and neighborhood are safe. One comment mentions ants in the kitchen — this really is not a big issue. If you keep the kitchen clean, you will not see ants. Nor is the airport noise a problem. We found our stay very easy and relaxing and we would stay here again on another trip to Lisbon.
One thing we wish we had known is that one of the bedrooms is only accessible through the courtyard and not contiguous with the rest of the flat. This made a difference to us but may not to others. If it was mentioned in listing, we missed it.