Had a lovely stay at Wim's place. He was an excellent host - gave us good directions to get to the house, was waiting for us when we arrived in Madrid, was very helpful and had plenty of maps for us to use to get around the city. The apartment is exactly like it says on the website - only thing is that the bedrooms are right on the street so it gets a bit noisy in the mornings. Also the apartment is located about 10 metro stops outside of Madrid city, so that's something to bear in mind especially if you're going to be out late at night, after the metro has stopped.