We stayed a week at Juan & Ricardo's apartment. It was a great stay.
Ricardo was waiting for us upon arrival, even though we arrived earlier than the expected time. Apartment is beautifully designed and very clean, just as seen in the photos. All required amenities were supplied for us (even a coffee machine with capsules, dishwasher etc..)
Ricardo was extremely helpful and gave us some tips about places to visit and recommended restaurants.
Apartment is located in a central area of Madrid (GranVia/Chueca) and close to all the main attractions of the city. We hardly had to use the metro, due to the central location of the apartment.
Few minor things that can be improved:
1. water pressure in shower is a bit low
2. shower drain is slow
3. bed is a bit narrow
4. WIFI is not accessible from the bedroom.
to sum it up - VERY RECOMMENDED! :)