We stayed here for a week in early July and really enjoyed Barcelona and being based in the apartment.
The stand-out feature is the terrace which has a fantastic view. The weather was hot when we visited so we used it only for breakfast and after sundown - but this was a really special part of our holiday. Sipping a beer on the terrace, in the evening twilight whilst having a game of cards was a beautiful end to a day.
The apartment was nice and clean when we arrived.
We were met at the apartment on arrival and responses to any text messages was very quick.
The neighbourhood is lively with little shops, bars, cafes and restaurants.
We enjoyed evening walks around the neighbourhood - and - further afield (only 25 mins. to Park Guell and 20 mins to Sagrida Familia - both are recommended 'sunset trips').
The apartment is only about 4-5 subway stops north of the tourist centre (about 15-20 mins. 'door-to-door). We thought this gave us the best of both worlds - quick access to all the sights whilst allowing us to stay in a 'proper' Barcelona neighbourhood.
The apartment itself was homely - not large - but well proportioned with two reasonable sized double bedrooms. It would be good for 2, 3 or 4 people.
One thing people should be aware of was the AC. There was a very effective AC unit in the sitting room but in neither of the bedrooms (although both had desk type fans on bedside tables). Because we visited in the summer we found it a bit warm to sleep at night.
In summary - We would love to visit Barcelona again and would happily stay at this apartment.