This is a great apartment in a nice location. We stayed there for vacation for 5 nights. Everything in the description is accurate, the apartment is clean and well managed, the hosts live nearby and are easy to access and communicate with.
Although it's a first floor, there is a ground floor in the building. Everything seems to be quite safe there. No security box provided, but we felt fine to leave our stuff there for day trips.
The hosts were very friendly and well prepared. You get local map with suggestions on local restaurants, sightseeing and shopping.
The only downside is that nearest subway is about 10 min walk. However, you can walk to Plaza Catalunya (15 min), and a lot of good places are just around this neighborhood.
Overall - great experience