We had a great stay at David and Luis's flat. The flat itself is really lovely, very spacious, well-equipped, good storage, excellent air conditioning, and comfy beds. The location is incredible and despite being on quite a busy road, the flat is set very far back from the street so it is absolutely silent.
The hospitality was excellent: check-in and communication were great, and when the wifi went down (due to a network issue affecting the whole area of Madrid) Luis went out and bought a portable wifi hub for us so that we could access the internet.
We would 100% recommend this flat!