It was 4 of us travelling and all of us agreed that the apartment was a perfect choice. Everyone had enough space and it is still possible for 5 people to stay there with out any inconveniences (there are 3 separate bedrooms).
Andrea is just a super host! She helped us with all possible directions from the airport and was always online until we've finally checked in. Also she gave us a lot of useful tips and instructions that helped a lot during our stay in Barcelona. She was ready to give advice about the restaurants and in general was always responsive.
The metro station is located just in front of the building and just in approximately 10 minutes you can reach any destination in the city center.
Only one minor comment: be ready that you may hear your neighbors, but it is a common thing in old Barcelona buildings (it's my 3rd trip to Barcelona and it was always the case). So if you want to feel the spirit of the city you will anyway face it :) It was not a big issue, since the neighbors themselves are quite (which is also expected from us as the guests).