The apartment is spacious and has air conditioning in every room. The communication from the owners is great. Even with the small critique below, we would stay here again.
The location is a bit of a double edged sword. It is right off Gran Via with easy access to several metro and Renfe stops (Callao, Sol, Gran Via, etc.). The other side of that sword is that there is a lot of night noise. The apartment is just above the ground floor so you hear all the traffic on the street. The interior bedrooms are better, but the living room and the front bedroom are not great for light sleepers.
If you are driving, be aware that the traffic around here is crazy and the public transportation in Madrid is fantastic. You’ll pay 38€ a day to park anywhere downtown while a metro/bus trip will cost you 1.20€ per person. Taxis to and from the airport are a flat rate 30€ to the city center.
If you want to be in the center of the action, this is your place. Just bring a fan or sound machine to help mitigate the street noise and, for goodness sake, take public transportation.