We really enjoyed our stay in this apartment. We came with 4 adults and 2 children, I think this is the maximum you can fit in there if you don't stay inside too much.
It is only a few minutes to walk to the nearest metro, and all neccesary stores (food, pharmacy, bakery, ...) are within walking distance.
We had an emergency on our first day in Barcelona (acute dental problem). Thanks to our host, we were able to get to an English speaking dentist within 1 hour. They really saved our city trip! Thanks again!