Everything was wonderful. Hosts react very fast - for example, we asked for a new frying pan in the evening and it was in our hands next morning. The apartment is clean, location is perfect from any point of view - supermarkets are nearby, Sagrada and Cathedral are 15-20 minutes on foot, metro and railway station are 3 minutes. Kitchen is well equipped with all necessary stuff. We spent 6 nights and all were quiet except one night when the neighbors from the upper floor (Asians, Chinese, I think) were doing something strange almost whole night and we had to move from the bedroom to the living room and sleep there.
We were in January there and it was +10 C outside and quite cold inside (at first), in spite of the fact that all rooms are equipped with good quality electric radiators. We succeeded to solve this problem and keep rooms warm by closing all the doors connecting the main long corridor with all other rooms - we discovered that the cold is coming from there. Be aware that if you switch all radiators together and use the kitchen electric devices, there is a chance of main electric switchboard deactivation (it is located inside the wardrobe on the left from the apartment door and you have to put the proper switch into the upright position).
But in any case this is not a fault of the hosts - just the construction of southern house.