It is an old apartment that was probably split in 2 for rentals and there's a private corridor as entrance of both apartments. The apartment is very comfortable but I would say it would be difficult to fit more than 4 people since the bathroom is really small - and as you probably have all the same schedule it won't be easy to get ready. Kitchen is fully equipped but we didn't use it much.
The only downside was not being provided extra blankets or towels - we had to find some stuff in the cabinets since they were not enough for our needs/cold. But we believe that at least the blankets issue was due to the unexpected temperature change in late September and won't happen much.
It has a very good location in Eixample - close to cool restaurants, stores and bars! It is the trendy area for enjoying BCN as a local! Since it is an area with much traffic and people you can hear some noise from the street but it is totally fine.
The hosts are very easy going and the communication was super easy. They even let us leave the bags after check out in the private corridor of the apartment and meet at a later hour - They definitely tried to fulfill all our requests even when not entirely possible.
I would recommend to anyone and will probably stay here again soon!