Flat is quite nice and ideally located in the very centre of Barcelona.
However the neighbourhood is quite busy at night during weekends and the windows only have single glazing. You'd better bring earplugs.

Lack of flexibility for the check in. We arrived at 8:30 am in Barcelona airport and were only able to get the keys a 4:00 in the afternoon.

Apart from that Manuel was nice and helpful; he indicated to us a locker room where we were able to leave our luggage.