I just spent a few days there - here are my thoughts:
+: amazing location: 1 minute from Gran Via, 5 from Del Sol
+: great communication all along
+: the 2 bedrooms and 1 living room, even if small, are perfect for a family of 4
-: some parts of the apartment look “tired” (doors, mattresses and bunk beds)
-: noise, as there was work done in the building itself and in the one in front, from 8am to 10pm. Nothing that the owner can obviously do much about. Good to know though for light sleepers: a bar is located just downstairs and operates till 2-3am
Overall, we liked our stay as the location is just exceptional and was our main focus for the few days we were in Madrid.