The apartment is on a fantastic street, right in the middle of Madrid Centro. Everything is within a short walking distance. The Sol transit station is a few blocks away if you need the subway. That said, there is some street noise, particularly on the weekends. The bedrooms are in the back, off the street, and are pretty quiet, but the living space is quite noisy at night.
Check-in is at a shop a few blocks away, so you will have to haul your luggage on busy city streets. Not a problem for us, but it might be for some people.
The apartment itself is huge! Two large bedrooms, and three brand new remodeled bathrooms.
The kitchen is nice, but sparsely appointed. Plenty of dishes and cookware, but no spices, no cooking oils, etc. There are many restaurant nearby, but if you plan to cook, be prepared to purchase all of your cooking needs.
The apartment could use a few homey touches. There were no extra pillows or blankets, and virtually no decorations. I would stay again.