Lovely apartment! Felt so nice to open the window and sit on the balcony on chilly mornings. Stayed alone, didn't feel unsafe. Even though it's one floor up, the elevator was very helpful as I had very heavy luggage.
Worked remotely for the two weeks I stayed, and the wifi worked fine. Had some snags and lost connection maybe once or twice on a call, but overall was able to continue my work as usual.
Laundry was also a plus, helpful that it was in the building and detergent was available. Also had dryers that worked well.
Location was great - just a block away from a metro station - although it's possible to walk almost everywhere. Royal Palace, Gran Via, Plaza Mayor, Prado, Puerta de Atocha - all less than 15 min. There are also two big supermarkets in the same square as the metro station (one is open 24hrs, very surprised by that in Europe) where you can get anything you need.
Would recommend!