This is a great place to stay for a day or two. It's super compact, but has everything needed like toiletries, an A/C, a mini-fridge, a small kitchenette, a table with two chairs, and a regular sized bed. The bathroom is extremely tiny and doesn't have proper noise insulation, so be comfortable with whoever you're traveling with (lol). The only complaint I had was that the bed is very squeaky and isn't the most comfortable, but again if you're only staying for a few nights it's fine.
The location is extremely safe, and picturesque! Super close by to the park, and has many shops and good restaurants around. Madrid allows Bird motor-scooters, and there's plenty around the apartment all the time, so it's perfect for traveling. Taxis had no problem finding the place.
Alain wasn't able to meet us, but he provided a number to his friend who helped us in. He allowed us to store our bags early and actually check-in an hour early since it was possible, (Definitely needed after a long red-eye flight.) All in all, I will return if I need to stay in Madrid for a short time!