Diego may be the best host I've ever had. He did everything he can do to solve the problems we had, suggested good local places. He was incredibly hardworking person, he is very responsive and friendly. Thanks for everything!
The flat was good as well. It is very central, enough for couples or solo travelers. If you stay in Madrid for short time, this flat is especially for you.
The flat doesn't have so many cons. An elevator may be good :) the only real con is the air conditioner. It is very noisy. I can sleep under any circumstances and it is like a white noise to me but it may not be very suitable for the people who wants silence during the night.
Overall I suggest the place if you want to stay somewhere central, clean and has a good host!