We had a great stay at Christian and Felix's apartment.
First of all the apartment is exactly as portrayed in photos, it's modern and clean and the amenities provided were everything you need.
The location is ideal, with tourist hotspots such as Sol and Plaza Mayor a 10 minute walk away. We were able to see and experience the majority of Madrid's central attractions by foot from the apartment, which was everything we were hoping for.
Christian was also a great host, his communication was clear and friendly, and he made our stay all so much easier from check in through to check out.
My partner and I would highly recommend Christian and Felix's apartment to anyone wanting to visit Madrid and looking for luxury/comfort/location all in one place.