Everything was great! Carlos sent exact instructions on how to get to the apartment and where everything was located nearby. Communication with him was excellent.
The apartment is located walking distance from all the major sights of Madrid (we only had to use the metro once).
On the weekends the bars stay open until late and there are many street parties that last until 3 in the morning. If outside noise bothers you I wouldn't recommend the apartment because the walls are a bit thin and we could hear people's conversations as they were walking down the stairs as well as the party noise.
Besides that it's a perfect apartment to rent for 2-3 people. Simple, excellent location and exactly as seen in the pictures. Highly recommended!