The host was unresponsive during check-in. I had messaged them my expected arrival time four days before and they never confirmed if it works for them, nor did they respons to my three follow-up messages. When I arrived to Madrid I hoped that the host had seen the message and will just show up, however no one was at the flat at the time I said I would be there. It was only after I contacted the AirBnb support, the host showed up, 15 minutes late (although it is hard to be "late" when the check-in time was never confirmed) and gave me the keys.
Otherwise a great place, great location.