Great apt. The best thing are the large windows all around, which give much light and nice views. It is very clean and I personally like the minimal furnishing a lot: two sofas, two tables, some chairs, and apart from those a lot of space to walk on (which was very convenient with the small kid I had with me). Because of exposed tubes for heating, the apartment can get very hot when central heating is on, not a big issue though.
The location is the real plus value of this place. It is at the center of all the places a tourist is going to visit. And 30 seconds from one of them, the Plaza Mayor.
The host is very quick at replying. The experience with the checkin was not the best. I was told that the apt was going to be ready at 3, but that I could leave my luggage, which I did, and then check in later. Then went for lunch with a group of friends. From 2:30pm till 3:15pm I got 10 messages saying the apartment was ready and I should hurry up. I am not sure if the host meant that I should be checkin in exactly at 3pm, or I should be ready to go when the apt was ready, but I never seen such a request in my life, and if that's standard on airbnb then I am sorry.