The apartment is in a fantastic central location - It's steps away from the La Rambla, gothic quarter, a major transportation hub (including the buses to the airport), and just a 20 minute walk to the Vila De Gracia (a wonderful neighborhood) along the grand Passeig de Gracia street.
The apartment is also clean, quiet (even though it's just a block from the busy Placa de Catalunya), and has lots of light. It fit my family of 5 (including a 4 year old) very comfortably during our 5 day stay. The apartment has two large queen sized beds, two twin beds, and a large couch that can convert to another bed. The apartment building has a quick elevator to the fourth floor and a friendly doorman during the weekdays.
Additionally, Arina and a partner of hers (Nina) are very accessible and incredibly responsive if any issues arise during your stay.
I highly recommend this apartment and would stay here again.