Many apts. say "great location" but this apt. is the "Best" location. We have stayed in Madrid before. This apt is exactly central to all tourist spots. It is in a nicer area - more upscale stores and restaurants- than others. 5 min to Puerto del Sol metro which has all the connections to all the metros. Easy walk down pedestrian streets to El Prado, Retiro, or the Palace. Taxis are right on the corner. There is a pharmacy and a grocery store Right Next door!
The apt was very clean and had everything you could need for living - large refer, micro, stove, wash machine, hair dryer, etc. And our favorite was LOTS of hot water and water pressure. I loved the balcony and watching the people on the street.
Oh, and because it's on the 4th floor it was very quiet. And if that wasn't enough there is an automatic metal shutter that completely blocks light and sound at the touch of a button. So there was no noise even on Saturday night.
The heater/air conditioner was very modern with a remote control and easily heated the apt. We didn't use the air con while we were there.
There is an elevator altho it doesn't go to the floor of the apt. You can stop either above or below.
One thing to watch out for - if you are older person or not a small person, the bed will give you trouble. It is blocked in on 3 sides so the second person has to climb over the first person to get out of bed. Also, it is not a large bed. We are small people but it was small. Also, the mattress is very thin so if you are heavy, you sink to the bottom. And the blanket is 30 cm thick 1 inch thick. No other blanket is available.
Other than the bed, it is a perfect apt - clean, great location, everything you need to stay, and plenty of hot water and ac/heat.