We (parents and two children) stayed 10 days in Arrates apartment, which is indeed a house of its own between the higher surrounding buildings. The photos are well taken, but do not lie - there are two nice sleeping rooms, a living room, a small terrace and a big roof terrace, where we had both breakfast and dinner a few times.
The house was great for relaxing (wifi working nonstop) when we were not on the nearby metro to the city or taking the children to the beach almost every afternoon. The nearby bus 26 ran every half hour to the beach and back, although we often walked back, 3-4 km.
The surrounding neighbourhood was very nice - topped by the small Plaça de Masadas just 200 meters away, where we had dinner 4 different places.
Arrate answered promptly whenever we had questions. We would gladly stay again here next time in Barcelona.