Joan's place is good as a base for your trip. It's small but if you just need somewhere to sleep it's fine. It's not as bright as it looks in the pictures. The balcony windows are the only windows that let in any light as the others in the flat all open onto the elevator shaft.
It's well located with the metro only a short walk away and the Sagrada Familia is only 10 minutes walk too.
We didn't meet Joan but he kept in contact and made sure we knew everything we needed to for the online check in and how to use the digital keys.
There are lots of very nice cafes and places to eat in the area. We really liked Lilo's for brunch and Gigi Von Tapas for dinner.