We were there for only one night as a group of 5 friends.
The apartment was very beautifully renovated, design and modern and very clean. There was enough space for the 5 of us although an extra bathroom would have been perfect. The apartment was also amazingly located right next to the Sagrada Famila so if you intend to stay around this area this an excellent place to stay in.
The only thing to complain about was the checkout process which was a bit rough as we were hard pressed to leave the apartment as soon as the we were supposed to, we only were late for about 10min but you could see that it was bothering them. The check in process was very simple though and the receptionist was very friendly.
All the apartments in the building belong to a company so it felt more like a hotel than an Airbnb stay so if you're looking more to spend time in a local's apartment, maybe this is not the best for you.
However, I still recommend this place if you want to stay in a very nice and modern apartment in the heart of Barcelona right next to tourists locations!