We booked this apartment as a treat for the end of our trip around Spain and would recommend it. It has a nice feel - sleek yet comfortable - and is equipped with everything you need. The highlight, of course, is the roof terrace which offers a fantastic view over Barcelona and which is perfect for a relaxed breakfast or aperitivo. One thing to bear in mind is that the stairs leading to the terrace are quite steep, so it may not be best suited for those with slightly reduced mobility, although the building itself does have a (much-appreciated) lift.
You couldn't wish for a better located apartment: it is located less than five minutes' walk from Universitat, a public transport interchange, making arriving from the airport and getting around the city by bus and metro super easy. It is also only a short walk to Plaça de Catalunya. The immediate area feels slightly calmer, yet you have a bakery, 24-hour supermarket and a lovely, chilled bar restaurant ("Beam"- highly recommended for a mojito, gin or for breakfast) practically on your doorstep.
Esther was also a great host: pleasant, communicative and informative.