Great apartment and hosts!
We have stayed 4 nights and enjoyed the time.
The room is quiet, bathroom is not in the room but it is at the door in front.
Location is great, you have many places to go out and the whole Madrid center is walk-able easily from the apartment. We only used bus once when went to Sorolla museum, which was located further from the center.
Unfortunately, we did not meet Vereniz during our stay (we woke up later and spend whole day out until late night). Javier had explained everything and was very helpful recommending close places to have breakfast and dinner.
At this place, we felt as locals and had a great time!