There are two caveats to this review: 1. We were coming from the West Coast of the US, and 2. There is construction going on nextdoor (behind) the property. Because of the confluence of these things, it was not a good stay for us.
We arrived Saturday evening, and had issues checking in. This property is company-hosted, and they assume you will have a working mobile phone upon arrival. This is probably a good assumption for European travellers, but it wasn't for us. We followed the agreed-upon instructions of emailing (using the airport WiFi) when we thought we were 30 minutes from arriving. However, once we arrived at the front door, no one was there and it took close to 2 hours to be let in and get the check-in completed.
The apartment is on what is essentially an alley off a typical city street. The placement of the bed is with your head under a window on the alley. If there's noise in the alley (uncommon), you will hear it. If there is noise on the main street, you will likely hear it. Cars and trucks just driving past are not really an issue, but at 03.30, the city empties these three huge trash bins which sit at the entrance to the alley. This will wake you. It's 15 minutes of pneumatic hissing, engine revs and air brakes.
At 08.30 Monday, the jackhammer started and didn't stop until past 17.30. Again, for people not hit with a 9-hour time difference, this may not have been an issue. For us, it was quite miserable.
Our unique challenges aside, the location is fantastic, and the neighborhood felt safe. It's very close to the easy metro and La Sagrada Familia, with plenty of markets and restaurant choices within minutes' walk.
Just be aware that until the construction is done (which I would guess may be a year away), do not expect to be able to rest at the apartment during the day.