We stayed in the apartment for 5 nights recently (2 adults & 2 teenage kids). The apartment is as shown in the photo's and was absolutely superb. It was almost midnight by the time we got there, but that was no issue and Dani met us as we got out of the taxi, brilliant service. The apartment was missing a few minor bits (kettle & iron) so we dropped Dani a note and they were delivered a few hours later, brand new.
The apartment is very spacious and we had loads of room, the TV came equipment with Netflix, and HBO so plenty of English channels available.
What really sets the apartment off is the location, it is right in the middle of everything. Located between 2 major metro stations (Sol & Gran Via), its only about 50m off Sol Square which is always buzzing. There is a 24hr Carrefour Express just up the street and loads of restaurants and bars in the local area. It would be difficult to find an apartment in a better location in Madrid as a base for sight seeing.
On one or two of the evenings there was some noise from the other apartments (small parties) but it never went past mid-night and was not really an issue. We would definitely stay there again.