Our family of five spent a week in Quim's lovely flat in central Madrid. Everything was as advertised or even better. We had plenty of space, beds were comfortable, and everything was spotlessly clean.
The flat is located on the top floor, so traffic noises didn't bother us. There is a big grocery store on the opposite side of the street and also 24H grocery store nearby. The major Madrid museums are in walking distance, as well as huge Retiro park, and number of excellent restaurants.
Quim and Isabel welcomed us warmly (there was a homebaked cake for us!) and responded very quickly to any questions we had prior and during the trip.
I can highly recommend this flat, a true gem.