The first thing to say is that we would absolutely stay at Miguel's apartment on a future trip to Madrid. Miguel is a perfect host, helpful without being overbearing. He left us a bottle of wine, some fruit and basic foods in the fridge. The location is right near many of the major tourist attractions. Bear in mind that Madrid is a pedestrian city, so some walking will be required wherever you might stay. The Metro Stop (Tribunal) is about 300 m away.
The apartment has a well equipped kitchen, two rooms plus a bathroom, and good security. The value is good for the center of Madrid. Nevertheless there are a couple of drawbacks that the visitor should be aware of. The balcony/terrace is a very nice space but quite sunny in the afternoon. Apparently an awning or cover is not permitted since none of the apartments have one, but in the summer months it sure would be nice. The balcony overlooks a lively square with several restaurants and it is nice for people watching. On the other hand the party continues all night in Madrid and you can hear that. We also heard that one of Miguel's neighbors has a small dog that barks occasionally. If you are a very light sleeper you might consider staying elsewhere, otherwise this place probably cannot be beaten for value and condition.