This flat was perfect! The bedrooms are nicely sized; not small but also not too big. The decor is simple and efficient. The bathrooms are modern and solid. The heating and air conditioning are effective and very familiar to Americans (central with internal ducting).
The furniture is a little different than the pictures, but it was quite comfortable. The couch in the living room is a sofa bed, but we didn't use it as a bed. It was still quite comfortable as a couch.
The balcony is on a small street just a few meters from Las Ramblas and all the action of Barcelona. The apartment was quiet the entire time, though, and so peaceful. There was only one time I could hear noise from outside, and that was when some teachers were leading about a hundred school children through the street right under our balcony one morning. Even then I could only hear the cacophony from the living room; the bedrooms are in the back part of the apartment, and I could not hear any noise back there.
There were only four of us on this trip, so we used the third bedroom as storage and a dressing room for the couple with the smaller bedroom. This worked out nicely for them since they did not have an en suite bathroom.
There is a "light well" for the back bedroom as is common in Spain. The window shade is not opaque so there can be a bit of light greeting you in the morning or during a full moon. My wife is a light-sensitive sleeper, though, and she had no trouble with it.
The Wi-Fi worked well, and there is also a phone, though we didn't use it. The kitchen is small but efficient and very modern. It included all the appliances and cookware we needed to feed ourselves when eating in. We did discover the coffee maker was broken; but a single email to our host got a quick response and a replacement coffee maker was provided that evening.
The flat is in a great location. It is situated just a block away from the Bouqueria, a fantastic outdoor market with every kind of fresh food you can think of. There are quiet little restaurants and shops down every street in every direction. The more touristy Las Ramblas is just outside and the Liceu metro station is just 50 metres from our front door. The whole journey is very accessible since there is a lift in the apartment and also a lift at street level down to the subway. This was a much appreciated feature for our senior citizen companions.
Loved the place. Definitely would stay here again. The only thing I would change is that we will stay longer in Barcelona next time, because we did not want to leave so soon.