This is the perfect apartment for a visit to Barcelona. The space is very clean and well-designed with many thoughtful touches that make it very comfortable. It is extremely close to Sagrada Familia and convenient to other sights yet sits on a leafy and calm street. We particularly enjoyed the balcony and hearing the bells from Sagrada Familia. Laura is a lovely host, and even called us a large taxi to the airport that fit all of our luggage.
I don't agree with concerns raised in other comments about the noise. This is an apartment in the middle of the city so it is to be expected that you can hear cars from the bedroom; any other expectation is unrealistic. The windows are high quality so the noise is at quite a low level - you can hear the cars driving by but we didn't hear any honking or sirens. We visited on a weekend and the biggest holiday of the year (Nit de Sant Joan) and slept well despite the fireworks and other festivities because the windows blocked most of the noise.
Highly recommended!