The apartment is pretty cozy, located also close to the center of Madrid (abt 20minutes walking). If you prefer to take the metro, the station is 3 minutes from there.
I wouldn't recommend this studio for people who have sleeping problems - it's quite loud there as neighbors' windows were very close. On the other hand, you can always use earplugs - it's what I did and since that time I slept like a baby.
Also, once we got there, we found out there is no wifi but the host bought us mobile internet cards, which could be used on our devices. So, make sure to ask abt it beforehand if you plan to work remotely from there.