The place is worth 5 stars only IF the smoke situation is solved.
We had a pleasant stay, the location is perfect for visiting Barcelona since its quite central and has very good connections to anywhere in the city.
The apartment was clean and cosy from the inside as well. The only downside was the smoke that comes in from the Kebab shop below. The kebab shop itself is a nice convenience, just below the apartment but the amount of smoke that comes INSIDE was very unpleasant. It could be dangerous for someone who has health problems due to smoke etc.
I would recommend this place 100%, but before make sure you ask the owners if they fixed the smoke problem.