What more can I say about the experience? Madrid is nice, the spanish people are friendly, the country doesn't differ that much with the Netherlands, except for their eating schedule. The students were about as I expected: stronger on the theoretical issues, not very experienced on the practical side and they need to work on their English.
Thus I have finished another challenge to myself. The hardest part was the preparation. But you know what they say: "Train hard, win easy" :-)