Reynaldo is super-sweet, he will go above and beyond to make you feel welcome. The room is in a very nice location, central, close to amenities and local attractions. The flat is clean and well equipped.
Slight downside is the radiators not being warm, but a portable heater was provided and, with 20 degrees Celsius in early December, I hardly used it.
Strongly recommend staying with Reynaldo and I will most certainly look him up again next time I'm in Madrid.