The apartment is very spacious with everything you will need in it. We were 2 ladies with 4 kids total including 2 year old. There was a high chair available and crib. We were given plenty of blankets, towels, soap, toilet paper... and it was great to have a washing machine inside the apartment. There is a conditioning/heater in every room. The location of the apartment is the best part especially if you come with little kids. There is a park with the good playground right by the apartment building- you can see it from the apartment balcony. So, when we were tired of sightseeing, we just spent a day walking around and kids were happy too. There is grocery shops of all kind and cafeterias on every step of the way. We even got to see a parade, festival and holiday celebrations right next to our place. There is also few famous places to visit in walking distance from apartment. Several metro stations is also very close, as well was a train station to go to Monsterrat!
Andreu was a very welcoming and helpful host.
The only problem you might have is one bathroom, but we managed pretty well:)