Fantastic place. It sits between two metro stations, and it's bordered by two supermarkets. Dead easy to walk or take public transport to the very heart of Madrid.
Luis is a great host. I injured myself soon before arriving at his place, and he took care of me while I got better. It was the perfect place to recover for a few days, too: large, comfy bed, very quiet bedroom, and a well-equipped kitchen and bathroom. I very strongly recommend Luis' place!