Amazing location, great size and layout. It's a perfect size for a small family. It has great closets/storage and would be suitable for a longer stay as long as somewhat worn couches/chairs are not a problem for you.
It's within walking distance to la Ramblas, Passegio Gracia, Sagrada Familia (20 min), Park Guell (30 min). Great restaurants nearby. Also nice and quiet despite its prime location.
An early check in was made possible, and after a long flight with a baby this was extremely helpful.
A crib was also provided for our infant and was already set up upon arrival which was greatly appreciated.
Basic living/cleaning supplies (e.g. soap, dish detergent, laundry detergent, etc) were provided which was also a plus.
Lastly, while everything was clean, the apartment felt like it was due for a deeper "spring cleaning" to get at some of those little things that a normal clean doesn't get. Not a big deal, but may bother someone who is very particular about these things.
Overall we very much enjoyed our stay.