Wonderful host, great location, tastefully decorated and a very clean apartment.
I want to add that Oscar was extremely gracious. We were arriving @7:30 am. He promised in advance that either he will let us check-in early or at the very least keep our luggage. We were at the apartment before 9. He was waiting for us. He was also available to help any time I called him. I highly recommend the place - I would not look for any other place if I am to visit Madrid again.
Just one small thing. There is construction going on next to the building, so there is a bit of noise because of that.