It would be very hard to have a better location for visiting museums and good restaurants. This is right near the Palace and the Opera, and the Metro is right there at Opera and Plaza de España, and also at Principe Pio, about a ten-minute walk. Many useful city bus lines run through Plaza de España. For non-Kardashian shopping, Gran Via is about a ten minute walk.
If you have a large group or several visitors, the three baths are very convenient. We were there for 10 weeks, and used the kitchen quite often. The stovetop, oven, microwave, toaster, fridge and dishwasher were all clean and operating optimally. The hot water is superb, even with someone showering with the dishwasher or clothes washer running simultaneously.
The building is old, and the downstairs public spaces could certainly use refurbishment, but that has little impact on your stay. The elevator is small but very reliable.
Finally, José was a superb host. Response was essentially instantaneous and any concerns were dealt with promptly and thoroughly. Although we just left Madrid, José’s hospitality and care have already influenced us to start planning our return trip to Madrid.