The apartment itself was incredible, 5 stars no doubt. Everything was clean, wifi worked great, the location is superb (between different major Plazas in Gracia, but still on a small and quiet street.
However, I can't put 5 stars for the check-in process. I have been given the link to open the door, but I arrived in the morning and didn't have internet on my phone. I have tried to call to the number that was given to me several times between 8:30 and 10, but no one answered. I had to wait for the store to open, buy a mobile card and only after that I could open the door. Took several hours, I was with a heavy bag, and it was cold outside.(
Apart from that, the apartment is a great choice and I highly recommend it. The big terrace is a huge + as well.