Overall a nice apartment in a quiet location. Not too far from the city centre but not so close as to be comfortable to walk in hot weather.
There are a good number of small shops and supermarkets nearby for basic shopping. A good number of small restaurants also near but not a lot of variety.
The apartment has more or less everything you need but could do with better cleaning. There is a lot of dust on bathroom doors that needs removing and sofa cushions need washing regularly. Otherwise, it is generally ok although it's not as large as appears on photos.
My main complaint is the power supply, which kept cutting out throughout our stay. There are no instructions in the apartment as to how to get it back, so we had to figure it out ourselves to avoid disturbing the host late at night. This is not helpful because it happened nearly every single day of our 9-day break!
There was also some work going on in the building with a lot of noise early in the mornings, which I didn't enjoy as I like my sleep during holidays!
You need to bear in mind that the lift in the building caters only for one person and the stairs are very narrow. If you have small children or disabled people travelling with you, this could be very inconvenient, especially in hot weather.
On a positive note, the host is very responsive and helpful. So if you need assistance, I am sure you will get it reasonably quickly. Would have been nice if the apartment had some maps and, perhaps, a guide book for Barcelona but this, of course, is not a demand. I just always found it very nice and helpful in all other apartments I've stayed in.
Overall, it's a good apartment; just needs some more attention to detail for the price.