Downsides: this is a business, so don't expect the traditional "host" experience -communication was poor. Very unresponsive. So if you have an issue or question after/ before standard "working hours" do not expect an answer. Pillows and mattresses are below standards. Wifi is weak, get a plan with your cell-phone carrier before you leave. 4 days is enough for Barcelona. Water takes a while to heat.
Great: this location is amazing, the best in the city. You can walk everywhere. Enough space for a family of 4-5. Very clean and modern. The balcony is wonderful, elevator is a HUGE luxury for this area. Host was accommodating, because our flight arrived early morning, as most US flights do -as we were allowed to check in at 9 am. The pictures are accurate. It's nice that there is a "super/site mgr" in the building (schedule is limited, not there 24/7).