Javier was an excellent host, this was my third visit to Madrid and yet he still was able to provide us with information that we didn't know about Madrid. He helped us arrange the taxi from and to the airport. As far as the place, the flat is located in a great location, there are several attractions that one can walk to. Plenty of nice restaurants and bars in the plaza where the flat is located, it has central AC for the hot summer and an elevator in case you have heavy luggage.
If I ever go back to Madrid, I would definitely stay at this location.