The appartment we had faced a quiet backyard, was clean and had everything necessary for a nice stay - including some packed croissants and Nespresso-capsules as a welcome :-). It shares the main entrance with another appartment, that may result in loud door banging and talking at gruesome hours..... Fast wlan!
Lots of restaurants, bars, cafes nearby, small 24-hour-supermarket across the street, larger supermarket in the same block. Within walking distance from Passeig de Gracia and Casa Mila, metro-stations and 15 minutes walk from sagrada familia. 5 minutes from the office, where you have the pick up the keys. Staff there was very helpful and friendly; we could leave the luggage in the office on the da of departure until late afternoon.
Only "complaint": on some photos you get the impression the apprtment has a balcony - it hasn't