Check-in was perfect: easy, quick, and safe. The location is awesome, very close to Madrid Central. Perfect for public transportation, not so much for staying with a car. Getting the keys at check-in was quick and easy.
The apartment lives up to the pictures. You can hear some noise from the neighbors, but none was too loud to wake us up. There was no Wi-Fi when we arrived, the host (Fran) got us a new router the next day. Cleaning was less than satisfactory: the trash can was gross on the outside, some dirty dishes, poorly cleaned floor. Unlike a hotel, it is expected that guests will cook; we usually find things that are used in small quantities: some spices, cooking oil, salt and sugar, enough coffee for one or two servings. Not the case here: the kitchen had no supplies. There are lots of places to eat outside, but we like to eat at breakfast and maybe one meal where we stay.
I would stay again if I went to Madrid by plane with the intention to basically just sleep in the apartment.