Pros: the location is fantastic, just a few blocks from Plaça Catalunya. It was quiet at night, the beds were comfortable and the bedrooms were air conditioned. The apartment feels spacious. There's a terrace up a short flight of stairs off the back of the apartment. The host is excellent and very responsive -- replaced the broken coffee maker the same day and was very helpful and accommodating.
Cons: the bedrooms are quite dark (which might be a pro for some people!). The bedrooms technically have windows but the windows open to a very tiny inner light well and this unit is at the bottom of a tall building, so very little light or air comes in. The kitchen is not that well equipped, but this is Barcelona, so you might not be cooking in very much anyway! We found it pricey for what we got, but we were also traveling in August, which is high season, so all the prices were high.
Overall four stars.