Mathieu's Gaudi Luxury apartment was perfect for our family of 5's first visit to Barcelona. It was well appointed, comfortable and a great location. The host met us at the apartment upon our trains arrival to give us a tour and helpful information and tips. They even ordered an extra large cab to transport us to the airport on our check out day. (it's actually very easy to hail a cab or get to the trains near the apartment ... but with our larger group & bags it was very nice not to worry about it.) Mathieu and Sabrina speak excellent English -- which is also a bonus - because sadly we speak little Spanish.
The Rambla de Catalunya & Passeig de Gracia are also excellent boulevards to stroll, shop and dine. Our only regret is that we didn't have more time!