Melissa's apartment is very well located - maybe 10 minutes walk to Sagrada Familia and 15 min walk to Casa Mila, 25-30 min walk to park Güell and to Barcelona Cathedral. The apartment is spacious by European standards - we were two couples and had plenty of room for ourselves.
The window of one bedroom faces the staircase so we could hear people coming up and down the stairs - not an issue though when using earplugs.
The kitchen is equipped with Nespresso Virtuo coffee machine - just a heads-up to bring your own capsules as we couldn't find those in the nearby mini markets.
There's a couple mini markets nearby in case one needs basic groceries. A nice cafe across the street were we had breakfast. And lots of cafes within 10 min walk distance :)
Check in was very efficient: Paolo met us in the apartment, gave us the keys and explained how everything worked.
Overall we are very satisfied and would recommend the apartment without hesitation.