My family and I were very impressed with the location of Avenida Gaudí 27! As soon as you walk into the living area there is a magnificent view of La Sagrada Familia as well as the walking area of Avenida Gaudí! The Metro was only about a 7-8 minute walk and there is a large number of grocery stores and pharmacies nearby.
The apartment is comfortable, with helpful storage (hangers, baskets, and a wardrobe in one room) and a well equipped kitchen. Since we had little ones it was great to have a washer! The Stay U-Nique staff made sure that basic bathroom toiletries were supplied (TP, shampoo, and conditioner, hair dryer) as well as towels for everyone.
Definitely would recommend this location for those that are interested in getting to know Barcelona!