We stayed in the apartment with 4 people for 5 nights and booked it because we already knew Malasaña to be one of the coolest neighbourhoods of Madrid. The location did not disappoint us, it is located in the heart of Madrid with plenty of bars and cafés nearby and only a few minutes walk to Gran Via and Puerta del Sol. A supermarket is right opposite the apartment. The place is clean and nice, it mostly looks like in the pictures. However, a major drawback for us was that we couldn't open the windows in one of the bedrooms and in the kitchen, because some neighbours had complained about former guests before and the windows had to be sealed. It would have been nice to know this in advance (there is air conditioning in the bedroom, however).
The hosts are very friendly and respond quickly no any questions and even welcome you with a bottle of wine.
All in all, it is a good place to stay at when coming to Madrid for a few days.