We were three friends and stayed for one week. The apartment is actually smaller than it appears on the pictures but if you think about it you won’t get a bigger one in Bairro Alto cause it’s only old buildings.
Check in and communication was really good and easy. The apartment looks nice but one downside is there is no window or ventilation in the bathroom and the kitchen equipment is kinda frugal (we asked for some more equipment and got it right at the day after though).
I would say the location is perfect for young people that like to go out in the night.
We expected Bairro Alto to be just a regular old town with some shops, restaurants and bars but it actually is like the party place for young people in Lisbon and you are right in it. So if you are looking for a nice and quiet apartment you should not book this one. However we enjoyed staying in Bairro Alto since you can just walk right out of the door and grab a drink.
During the day you can reach lots of sights by walking a few minutes and you got lots of restaurants in the streets around the apartment.