Andres was there to greet us as we arrived and gave us a good introduction to Madrid. Excellent location for the museums and Retiro Park, all within 5 to 10 minutes walk. Rest of the sights were all within walking distances (25 min to the Palace), so no need for transits at all. Lots of cafes and restaurants nearby. The apartment is at the back of the building so nice and quiet. There is no elevator in the building so if one has heavy suitcases, may be challenging (its only 2 floors up). Kitchen is fairly well equipped although dish washing liquid and disk cloth would have been nice to have.
We enjoyed our 6 days stay and would recommend it.