We spent a weekend in January with the five of us in Kristian's appartment. We were kindly welcomed by Kristian's girlfriend, who also gave us some tips for nice places in Madrid.
The appartment is just like the pictures. It was very clean, had comfortable beds, decent shower, just everything we needed, and was easily big enough for five people to move around. Best of all, it was an absolutely perfect location in the centre of the city, it's great to be able to explore the whole city on foot. I would gladly stay again at Kristian's place.