TL;DR : Just what you need for a week end getaway in Madrid ! Only one negative point : no wifi.
Details : A small but cute, clean and very functional appartment. The location in Barrio de las Letras is really great : central, beautiful, full of life. So many bars and little restaurants within 10mins by foot! I haven't had the need for a taxi in the whole week end. On the point of the wifi, we were told that we would receive the code by message but didn't, and the only networks in range seemed rather far away (only one or two bars). Then again, it may have been a communication mishap, benefit of the doubt :)