I didn't book the room for vacation purposes, but because I was kicked out of my accomodation and needed a place where I could stay while I searched for a new accomodation.
Elkim's room was the perfect place to stay at. I chose it because of its fair price and the wide variety of services offered, as well as its position - close to my office.
The apartment is a nice and comfortable. My room had enough space to bring in all my luggages, as well as a desk to use for working/studying. Also, the area is very quiet, which made working and studying from home a positive experience.
Elkim is kind and always willing to help make your stay as comfortable as possible. Also, he's very discreet. Same goes for his dog companion, Luka, a nice and friendly dog. Even if you're not a dog-lover, he won't cause you any troubles and will come to appreciate his company.
If you're coming to Madrid, I highly recommend staying at Elkim's :)