The location was a great jumping off point for experiencing Madrid. Centrally located with easy metro access. Airport is about 20 minutes away, too. Plenty of restaurants, bars, grocery stores, interesting shops, etc., nearby. The manager was attentive, responded promptly, and took care of requests right away. The food selection she stocked the apartment with was really nice.
The drawbacks, while not fatal, were the bathroom and the entry lock. The bathroom was miniscule. Whatever you're imagining, it's smaller. The front door lock required training and felt like you were solving a trick puzzle. It took quite a lot of practice as it was unnecessarily complex. The property manager did offer to come back for additional tutoring, so at least we weren't ever abandoned.
Those aren't reasons to avoid this property. They simply exist. No property is 100% perfect. The "primary residents" were my daughter and her boyfriend (I returned home after the first night). They said they liked it and would stay there again.
Interestingly, this property was once a store, I think. The window facing the front has some leftover signage and people occasionally pose in front of it for photos. To us, that was kind of a fun bonus and gave the place some added charm.