I had such a great stay at Ziad's place; the apartment is stylish and clean, and had everything I needed. Be aware, it is a 5th-floor walk-up-- but I even loved that because I appreciated a little bit of extra exercise ;)
Ziad was very good about keeping in touch-- even though he was out of town when I arrived, he arranged for me to pick up the key with no problems. Above all else, this flat is located in the most amazing, vibrant and interesting part of Madrid, in my opinion. If there is a better part of the city than Malasaña, I definitely didn't find it!
One thing I didn't realize (maybe I didn't understand, or Ziad told me and I forgot) is that there are 2 other bedrooms for guests inside the apartment. But that was fine as well, because everyone was extremely chill, and every room can be safely locked. If this is the neighborhood and budget you're looking for, I highly recommend Ziad's flat.