The apartment is in a nice, authentic area approx. 20 min walking from Pl. Catalunya, Las Ramblas and the Gothic area, 30 to the beach (take a cheap and reliable cab).
The apartment is nice, but not as spacious and cosy as it looks in the pictures. The sofa is quite old and filthy and we didn't want to sit on it, so were the chair pillows. The blinds in the single room were broken and couldn't be removed from their half way down position, so it was dark during the day and really light at night due to the street lights. The AC and Wifi worked very well.
Vanina is a nice host, very friendly, replied right away and offered us her help while in Barcelona.
As the apartment is offered as a nice venue for a friends' holiday, it lacks a second pair of keys unfortunately, which was a bit annoying when we had a different schedule during the day or at night, meaning I had to ring the other party up to open the door at night. So a second key is strongly recommended.
Some reviews stated that it is really loud, but it's a quiet street and I didn't need my ear plugs that I brought. It's Barcelona and generally people are a bit louder in Spain than in other countries, but totally OK with the noise (please note that we were there during the week though).
To sum it up: Nice, authentic location walkable to the centre, apartment OK but rather very basic standard and too many defects for the price. Friendly and reliable host. Only go there with family or very good friends, otherwise too small and lack of privacy. AC was a benefit. I think I would look for a different place the next time though, just for the price-performance ratio.