This is a great apartment in a fantastic area of the city. Communication with Carlos was extremely easy, as he replied to messages in just a few minutes.
The check in process was very easy due to the 24-hour doorman service that the building offers.
This is my favorite neighborhood in Madrid. There are many great food choices within a few minutes walking and you'll find any shopping you need. The apartment is also very close to the Retiro park, Cibeles, and about 10 minutes taxi to Puerta del Sol.
I definitely recommend this apartment to anyone visiting Madrid.