We had a great stay in the flat in Bairro Alto.
Not only this neighborhood is extremely well located (in the center of the city, Everything is walking distance for the flat), but also it is the heart of Lisbon night life (lots of bars, restaurants, cafes...perfect to go out). You really get a feel of the city in Bairro Alto.
Priscilia, our host made the arrival and the departure very easy - always available via emails or on the phone.
The flat was very clean, convenient (2 real bedrooms, with each 2 beds) and matches the online description. All the basics were there.
I definitely recommend Lisbon, Bairro Alto and this flat to friends and families.