I've spent 7 days in this nice apartment with very friendly host and I wish I can stay more... Below are more details:

[+] Very friendly and helpful host
[+] Excellent center location, with many shops, bars, restaurants, pharmacy etc. located on the same street. Walking distance to nearly all important Madrid sights.
[+] Well equipped kitchen, where I cook daily fresh sea food from the famous 'San Anton' market (200 m)
[+] Space room with everything I need.
[+] Very clean

[-] Air condition exists, but not functional because of infrastructure problems of the building itself.