This was a great place for my family to stay! The property is close walking distance to the red and purple metro lines (different stations) and the Estacio del Nord bus station which really open the city up (a 1-zone metro ticket is sufficient for basically all of Barcelona)
For major destinations, the beach is about a 25 min walk, La Sagrada Familia is about 20 min, and the Gothic Quarter is about 20 min. We never felt unsafe while walking around, and the city is very much designed with walking and biking in mind.
For amenities, there are two grocery stores on this block, around five cafes within 1 block of walking, and a large variety of restaurants in the direction of the Estacio del Nord a couple blocks south of the property.
Inside the apartment, everything was in excellent working condition, though it did take me a little while to figure out how to use the air conditioner. It was plenty of space for the three of us to unwind after a day of walking and tourism. The only downside for us (coming from a smaller, very quiet town) is that there is a lot of noise which comes with being in a major city; c/ de Napols is a fairly busy street at all hours, so there's lots of foot and vehicle traffic. Between that and the occasional cigarette smoke from the sidewalk (to which my wife is very sensitive), we weren't able to sleep with the windows open despite wanting to. This was fine as the windows did a good job reducing the noise.
Overall, I would definitely stay here again!