Great place, super well located and great price =)
Location wise you can't really do better. It is located right at the city center and you can easily walk almost anywhere worth going.
The room has a balcony which is super nice to have and makes it really fresh during the summer. The apartment itself is kind of old but hey, considering the price that is the last of my concerns.
The apartment has 6 other bedrooms (which only 4 were occupied at the time), a mix of long-time residents, people saying for a couple months and travelers like myself. Everyone there was super relaxed and friendly and great atmosphere in the house.
Overall a great experience and I absolutely recommend it if you are looking for a fun, cheap place that has all you need to enjoy Madrid!