Itiziar and Alfonso are incredible hosts.
Even if it's not a proper local flat(meaning where real people live all year), it is super-clean, perfect for 6 people but can go up to 8 with the convertible sofa. Beddings are very clean and also the most comfortable we've seen after few years of Airbnb. There were two pillows per persons ! Very fast wifi (usually it is slow and has issues).
The balcony is great to have some fresh air too.
Just below the flat, at street level, there is a coffee that belongs to Alfonso which also great to start the day with a fresh coffee and orange juice or to work a little bit with the wifi.

So very secure, clean, comfortable, located at 200 meters from the Sagrada Familia and the metro, 10mns walks from Gracia...
Check-in and check-out are smooth, possibility to store your luggage in security when you check-out at 11am and your plane is in the evening so you can enjoy the reste of the day without all your stuff.

I would highly recommand for family or group of friends.