Unfortulately, our stay did not end pleasantly due to an attempted break-in. Apparently, the door to the building is often broken which means that anyone can just let themselves into the building to do what they want. It left us quite shaken and worried for the safety of our family (we have a very young child and a baby). Sergio (our host) responded very quickly and both he and Just tried to find a temporary solution to the window panes that were missing as a result of the break-in. In the end, we felt safer moving to a hotel which AirBnB helped facilitate.
Aside from that, we found the apartment to be ok. Location-wise, it was ok, it was about a 15 minute walk to Las Ramblas and other main tourist attractions. Metro was a short walk away. The apartment is very close to a pedestrianised street with many bars/restaurants/bakeries. The apartment itself had a few issues. First off, the interior of the building (stairs, corridors) look very run-down. Fortunately, the aesthetics of the apartment were better. Inside the apartment the main issue was the lack of ventilation in the bedrooms. No fan/AC in either of them. Only one room had access to fresh air from a balcony door but it was not ideal to leave the balcony walk-out doors open to get ventilation at night (didn't want mosquitoes getting in). The AC unit in the living room makes loud buzzing noises that would sometimes wake up my sleeping baby. The doors to the rooms were very narrow and did not block any noise that would have came from the living room/kitchen area (the doors were not typical doors, they were more accordion-type sliding doors). We also experienced sewage-type odors in the washroom. The last issue was with the baby cot...the mattress was too small for the crib so on the first night i woke up to find my baby crying because she managed somehow to slide under the mattress! I wouldn't recommend that crib as it seems unsafe.
If the building was safer and well kept, we would consider staying here again (if we didn't need a crib and if it wasn't in the heat of the summer when AC in bedrooms is a necessity.)