Luis' apartment has a perfect location indeed - it's in the center of the center of Madrid. It has an easy walking access to everything important, interesting, tasty and fun in the city. We didn't use and didn't have the need to use public or any other transport. At the same time we didn't have to walk a lot to reach the places we wanted to visit.
The check-in process was great - timely, organized, full of valuable tips and garnered with a bottle of tasty wine. Everything we asked, we got answer for with recommendations. The tips were well tailored for our needs and what we were looking for.
The apartment itself is spacious, stylish and has everything one may need. We slept well as it was quiet. Maybe the only downside is that there is not a lot of daylight and for ventilation you have to rely on an air conditioning. Which at some point gets a bit tedious but you can just turn it off and open the front door.