The space is small so I wouldn’t recommend for more than 2 people really but it was well kept with all the basic amenities. Check in and communication throughout the stay was handled by an outside company and very easy.
Location is about a 7/10. Safe neighborhood, stores and restaurants around the corner. It is about a 25-minute walk from all the main attractions if you are visiting as a tourist, however you can take the nearby 1 train on the metro to both of the main train stations which is very convenient if you plan any day trips outside Madrid.
Please note, there is no light in the staircase so you need to be careful or use a cell phone as a flashlight if coming home late (or after a few drinks!)