We stayed for 9 days, we enjoyed our stay. The apartment is large, air conditioning in all rooms, very good location, a nice balcony with a view of Sagrada Familia, we spent lots of time there, the apartment is well equipped with all the stuff for cooking, washing etc., we even had some treats in our fridge. The building has an elevator, which is important when you have large suitcases. The host was very nice and polite, allowed to check-in earlier. There is a supermarket (closed on sundays) just opposite the building and a few more nearby, Sagrada Familia is 5 minutes walk, taxis and metro nearby and parking lot just near the building.
We noticed just a few little cons, such as the water temperture in the bath changed to quickly from cold to hot and back, was difficult to take a shower, and in one room the AC used to make weird buzzing noise every now and then, at night it was difficult to sleep when it did that noise. Other than that - it is a great place to stay!