The flat is in very good location, just around the corner of a metro station and one of the major avenues (Gran Via) where lots of buses pass, and walking distance from the Sagrada Familia.
Also is quite comfortable, with a modern kitchen and bathroom, and a comfy sofa to watch TV. The bed is big and comfortable, and the bedsheets are good quality.
There's plenty of storage space for luggage and so.
The kitchen has most of the stuff necessary to cook, although I missed some basics (like cooking oil, salt, sugar, oil). The hosts provided some of this, in small sachets, which is good, but given that those items are cheap and non-perishable, it would be simpler just to have some of that there in small containers.
The building is new and with a lift/elevator, something that not all flat buildings in Barcelona have!
The cons were few:
* the AC unit refused to turn off once we managed to turn it on. That was a nuisance
* the TV is not a bit small for today's standards and is not a smart TV