I spent two nights at Luis' place and I have to say it was one of my best Airbnb experiences so far! Luis is a very kind person, we had some interesting talks and I was very surprised when I got a dinner invitation from him (something which doesn't happen so often). I would totally recommend him and his place to anyone going to Madrid. The place is tiny, but very nice and very centric (just 10 min. from Atocha) and you have all you need nearby (cafes, restaurants, museums etc.).