The apartments' location is very central, so we walked to most places. There's also a metro station a few minutes away. Plus, car/scooter/moped sharing if you fancy that option. The apartment was just as described, sparkling clean with all needed amenities. The mattress was firm yet soft and all rooms had fans (we visited during a heatwave and the temperature inside the apt was kept at an ok level). There are plenty of shops and cafes nearby. Also markets (for tapas). Communication with Alvaro was prompt and he's a tremendous host (helpful, nice, accommodating).
I'd totally recommend this place for your stay in Madrid!