In Brief... YOU CANNOT FIND BETTER.
I really do not know where to start, the apartment is EXTREMELY BEAUTIFUL, it is just as described, when we first saw the pictures we were scared they might be photoshopped but actually, in reality, the apartment is more beautiful than the pictures. The apartment is very spacious, it is newly furnished and very well decorated (which is something very hard to find in Barcelona) with the best electronics, utensils, and appliances. It is everything that we wanted.
The location is absolutely perfect, there are 4 well-priced supermarkets just on the doorsteps, and 3 more supermarkets that are a couple of blocks away (our favorites are Lidl, Mercadona, Consum). The bus station is literally 30 seconds away and the metro station is 2 minutes walk.
There is a beautiful garden 1 minute away from the house that my husband and I used to take our coffee and go to in the morning or afternoon.
While here I had the chance to go for a daily walk towards Sant-Pau (which is 3 blocks away) and then towards the Sangrada Familia. There are plenty of restaurants and coffee shops surrounding the house.
The Internet is very fast and the neighborhood is very safe and quiet.
Last but not least, Frederic's service was amazing, he directly responded to our messages he even installed an additional new router to improve the internet reception. Moreover, he continuously provided us with detailed information for having a smooth stay in Barcelona.