I had quite a few problems with this flat during my 45 nights stay.
Problem 1 - cockroaches, the first night we got there, we found them running around everywhere. We got really freaked out. After "cleaning", we still found dead or half dead ones almost every day for weeks.
Problem 2 - neighborhood, this is in Raval, not the safest in Barcelona, the street is dirty and stinky, you will find people sleeping outside of the flat, and/or come back to find your front door glasses smashed.
Problem 3 - the building is very old, and very closed to other buildings. There is an old lady with the TV blasting day and night, there is screaming babies on the other side, not to mention parties. The noise from neighbors made us call the police at one point. You can imagine.
Problem 4 - the listing is operated by a company, upon my arrival, they asked me to sign a legal document en Español. There is nothing in the flat, not even a toilet roll. During the stay, there is not much help from the company to resolve issues like a broken dishwasher, they took the broken one away and left a hole in the kitchen.
Problem 5 - the company lied to me, first they agreed for me to shorten my stay, and get refund for my unstayed 10 nights, since the neighborhood issue has caused me insomnia and really made an impact on our wellbeing and sense of security. I booked a new flight, but then they wouldn't refund me. Luckily Airbnb support helped me to have reasonable compensation. But the whole experience has made a huge dent in my Barcelona workaction.
So yes, here are the problems I find, FYI. I knew that the company has quite a few other flats in Barcelona, perhaps you won't find the same problem in other flats. But I believe the company should have treated the guests with care and respect.