The stay at Diegos place was really good. The apartment is very near all the important sightseeing landmarks and right away you are in the heart of the center. The place has everything you could need for a short stay. The bed is big and comfortable. The apartment is small but more than enough as you should be discovering madrid most of the day anyway ;)
Diego was super helpful and was eager to help if I needed something.
The Internet in the flat worked very well as I could easily take work meetings.
With all that said it’s fair to say I would recommend the apartment 100% if you are looking for a enjoyable stay in the center of madrid!