Bright, airy, spacious, and located right in the hub of Madrid, I would highly recommend this apartment. There were seven of us and everyone had their own room and bathroom and plenty of space for relaxing and spending time together.
Even though it was late November, we were able to enjoy the terrace on a few sunny afternoons. The kitchen worked fine for preparing meals, with plenty of dishes, silverware and pots and pans.
Carlos has provided extensive information about the area and things to do. The building is right on Gran Via, but sleeping was quiet as the apartment faced the street behind that was very calm. I would absolutely rent this place again.