Carol and Ivan's place is a perfect little spot in Madrid for 2-4 people, and Carol was a very nice hostess who greeted us at the door and showed us through the place. Located literally steps from Puerta del Sol and the Metro stop, its also in a very lively neighborhood filled with good food and drinks. We found many things to do just in the blocks directly around us. It's also very easy to walk to Parque el Retiro, the Prado, Plaza Mayor, and the Palacio Real de Madrid. We could not have been much better situated!!
The space itself was perfect for us 4, with 2 bedrooms and 2 bathrooms (both with showers, one located within a bedroom) and a small kitchen with all we needed in our short stay. Everything was clean and quite comfortable. Each room has lots of space and storage area, which we appreciated.
A couple things to note - the unit is on the 4th floor of a building with a sloping ceiling and low beams. Wasn't really a problem for us besides ducking here and there, but if you are quite tall it may not be your place. And while there are 2 showers, the one in the guest bathroom is very tiny--still useable for sure, but not meant for anyone on the taller/larger side.